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  • Publisher Correction: A universal principle for a rational design of single-atom electrocatalysts
    Nat. Catal. Pub Date : 2018-07-20
    Haoxiang Xu, Daojian Cheng, Dapeng Cao, Xiao Cheng Zeng

    Publisher Correction: A universal principle for a rational design of single-atom electrocatalysts Publisher Correction: A universal principle for a rational design of single-atom electrocatalysts, Published online: 20 July 2018; doi:10.1038/s41929-018-0127-0 Publisher Correction: A universal principle for a rational design of single-atom electrocatalysts

    更新日期:2018-07-21
  • Capture and characterization of a reactive haem–carbenoid complex in an artificial metalloenzyme
    Nat. Catal. Pub Date : 2018-07-16
    Takahiro Hayashi, Matthias Tinzl, Takahiro Mori, Ute Krengel, Jonny Proppe, Janne Soetbeer, Daniel Klose, Gunnar Jeschke, Markus Reiher, Donald Hilvert

    Non-canonical amino acid ligands are useful for fine-tuning the catalytic properties of metalloenzymes. Here, we show that recombinant replacement of the histidine ligand proximal to haem in myoglobin with Nδ-methylhistidine enhances the protein’s promiscuous carbene-transfer chemistry, enabling efficient styrene cyclopropanation in the absence of reductant, even under aerobic conditions. The increased electrophilicity of the modified Fe(iii) centre, combined with subtle structural adjustments at the active site, allows direct attack of ethyl diazoacetate to produce a reactive carbenoid adduct, which has an unusual bridging Fe(iii)–C–N(pyrrole) configuration as shown by X-ray crystallography. Quantum chemical calculations suggest that the bridged complex equilibrates with the more reactive end-on isomer, ensuring efficient cyclopropanation. These findings underscore the potential of non-canonical ligands for extending the capabilities of metalloenzymes by opening up new reaction pathways and facilitating the characterization of reactive species that would not otherwise accumulate.

    更新日期:2018-07-18
  • A happy couple
    Nat. Catal. Pub Date : 2018-07-12
    Frank Marken, Steven D. Bull

    A happy couple A happy couple, Published online: 12 July 2018; doi:10.1038/s41929-018-0113-6 Pairing electrosynthetic anode and cathode processes (either convergent or divergent) is essential to maximize energy usage/sustainability and to minimize waste. New approaches to pairing in electrosynthesis are needed and the use of a palladium film membrane by Berlinguette and co-workers represents an effective paired reactor prototype that couples electrosynthesis with chemical catalysis.

    更新日期:2018-07-12
  • Enhancing DNA sequencing
    Nat. Catal. Pub Date : 2018-07-12
    Jan-Stefan Völler

    Enhancing DNA sequencing Enhancing DNA sequencing, Published online: 12 July 2018; doi:10.1038/s41929-018-0120-7 Enhancing DNA sequencing

    更新日期:2018-07-12
  • Synthesis of reaction‐adapted zeolites as methanol-to-olefins catalysts with mimics of reaction intermediates as organic structure‐directing agents
    Nat. Catal. Pub Date : 2018-07-12
    Chengeng Li, Cecilia Paris, Joaquín Martínez-Triguero, Mercedes Boronat, Manuel Moliner, Avelino Corma

    Catalysis with enzymes and zeolites have in common the presence of well-defined single active sites and pockets/cavities where the reaction transition states can be stabilized by longer-range interactions. We show here that for a complex reaction, such as the conversion of methanol-to-olefins (MTO), it is possible to synthesize reaction-adapted zeolites by using mimics of the key molecular species involved in the MTO mechanism. Effort has focused on the intermediates of the paring mechanism because the paring is less favoured energetically than the side-chain route. All the organic structure-directing agents based on intermediate mimics crystallize cage-based small-pore zeolitic materials, all of them capable of performing the MTO reaction. Among the zeolites obtained, RTH favours the whole reaction steps following the paring route and gives the highest propylene/ethylene ratio compared to traditional CHA-related zeolites (3.07 and 0.86, respectively).

    更新日期:2018-07-12
  • The importance of industrial publications
    Nat. Catal. Pub Date : 2018-07-12

    The importance of industrial publications The importance of industrial publications, Published online: 12 July 2018; doi:10.1038/s41929-018-0119-0 Industrial publications are a very valuable and multifaceted tool for the wider catalysis community; they can foster the productive collaboration of university and corporate research laboratories, an essential partnership for the solution of important societal problems

    更新日期:2018-07-12
  • Fixation of gaseous CO2 by reversing a decarboxylase for the biocatalytic synthesis of the essential amino acid l-methionine
    Nat. Catal. Pub Date : 2018-07-12
    Julia Martin, Lukas Eisoldt, Arne Skerra

    The use of CO2 as a building block for the synthesis of bulk chemicals appears highly attractive but has not been realized in industrial biotechnology due to the complexity and costly energy balance of conventional anabolic biosynthesis. Here, we describe the biocatalytic preparation of l-methionine from the abundant industrial intermediate methional under direct incorporation of CO2 by reversing the catabolic Ehrlich pathway. Despite unfavourable chemical equilibrium (1/554 M−1), the decarboxylase KdcA revealed half-maximal activity for its reverse reaction at astonishingly low CO2 pressure (320 kPa). Accordingly, it was possible to synthesize l-methionine under a 2 bar CO2 atmosphere when coupled to an energetically favourable transaminase or amino acid dehydrogenase reaction. Similarly, l-leucine and l-isoleucine were prepared via biocatalytic carboxylation of 3- or 2-methylbutanal, respectively. Our findings open a biotechnological route towards industrial products and enable further syntheses involving the fixation of gaseous CO2 by simply applying decarboxylases in the reverse mode.

    更新日期:2018-07-12
  • Rational design of zeolite catalysts
    Nat. Catal. Pub Date : 2018-07-12
    Jeffrey D. Rimer

    Rational design of zeolite catalysts Rational design of zeolite catalysts, Published online: 12 July 2018; doi:10.1038/s41929-018-0114-5 The identification of organic structure-directing agents capable of tailoring the physicochemical properties of microporous materials has remained a challenge. Now, a unique methodology to design organic mimics of reaction intermediates provides a route to optimize the selectivity of zeolite catalysts.

    更新日期:2018-07-12
  • Separable Suzuki
    Nat. Catal. Pub Date : 2018-07-12
    Enda Bergin

    Separable Suzuki Separable Suzuki, Published online: 12 July 2018; doi:10.1038/s41929-018-0121-6 Separable Suzuki

    更新日期:2018-07-12
  • Catalysts for nitrogen reduction to ammonia
    Nat. Catal. Pub Date : 2018-07-12
    Shelby L. Foster, Sergio I. Perez Bakovic, Royce D. Duda, Sharad Maheshwari, Ross D. Milton, Shelley D. Minteer, Michael J. Janik, Julie N. Renner, Lauren F. Greenlee

    The production of synthetic ammonia remains dependent on the energy- and capital-intensive Haber–Bosch process. Extensive research in molecular catalysis has demonstrated ammonia production from dinitrogen, albeit at low production rates. Mechanistic understanding of dinitrogen reduction to ammonia continues to be delineated through study of molecular catalyst structure, as well as through understanding the naturally occurring nitrogenase enzyme. The transition to Haber–Bosch alternatives through robust, heterogeneous catalyst surfaces remains an unsolved research challenge. Catalysts for electrochemical reduction of dinitrogen to ammonia are a specific focus of research, due to the potential to compete with the Haber–Bosch process and reduce associated carbon dioxide emissions. However, limited progress has been made to date, as most electrocatalyst surfaces lack specificity towards nitrogen fixation. In this Review, we discuss the progress of the field in developing a mechanistic understanding of nitrogenase-promoted and molecular catalyst-promoted ammonia synthesis and provide a review of the state of the art and scientific needs for heterogeneous electrocatalysts.

    更新日期:2018-07-12
  • Sinter-resistant metal nanoparticle catalysts achieved by immobilization within zeolite crystals via seed-directed growth
    Nat. Catal. Pub Date : 2018-07-09
    Jian Zhang, Liang Wang, Bingsen Zhang, Haishuang Zhao, Ute Kolb, Yihan Zhu, Lingmei Liu, Yu Han, Guoxiong Wang, Chengtao Wang, Dang Sheng Su, Bruce C. Gates, Feng-Shou Xiao

    Supported metal nanoparticle catalysts are widely used in industry but suffer from deactivation resulting from metal sintering and coke deposition at high reaction temperatures. Here, we show an efficient and general strategy for the preparation of supported metal nanoparticle catalysts with very high resistance to sintering by fixing the metal nanoparticles (platinum, palladium, rhodium and silver) with diameters in the range of industrial catalysts (0.8–3.6 nm) within zeolite crystals (metal@zeolite) by means of a controllable seed-directed growth technique. The resulting materials are sinter resistant at 600–700 °C, and the uniform zeolite micropores allow for the diffusion of reactants enabling contact with the metal nanoparticles. The metal@zeolite catalysts exhibit long reaction lifetimes, outperforming conventional supported metal catalysts and commercial catalysts consisting of metal nanoparticles on the surfaces of solid supports during the catalytic conversion of C1 molecules, including the water-gas shift reaction, CO oxidation, oxidative reforming of methane and CO2 hydrogenation.

    更新日期:2018-07-10
  • A photoswitchable catalyst system for remote-controlled (co)polymerization in situ
    Nat. Catal. Pub Date : 2018-07-02
    Fabian Eisenreich, Michael Kathan, Andre Dallmann, Svante P. Ihrig, Timm Schwaar, Bernd M. Schmidt, Stefan Hecht

    The fundamental properties of a polymeric material are ultimately governed by its structure, which mainly relies on monomer composition and connection, topology, chain length, and polydispersity. Thus far, these structural characteristics are typically set ex situ by the specific polymerization procedure, eventually limiting the future design space for the creation of more sophisticated polymers. Herein, we report on a single photoswitchable catalyst system, which enables in situ remote control over the ring-opening polymerization of l-lactide and further allows regulation of the incorporation of trimethylene carbonate and δ-valerolactone monomers in copolymerizations. By implementing a phenol moiety into a diarylethene-type structure, we exploit light-induced keto–enol tautomerism to switch the hydrogen-bonding-mediated monomer activation reversibly ON and OFF. This general and versatile principle allows for exquisite external modulation of ground-state catalysis of a living polymerization process in a closed system by ultraviolet and visible light and should thereby facilitate the generation of new polymer structures.

    更新日期:2018-07-03
  • Interaction trends between single metal atoms and oxide supports identified with density functional theory and statistical learning
    Nat. Catal. Pub Date : 2018-07-02
    Nolan J. O’Connor, A. S. M. Jonayat, Michael J. Janik, Thomas P. Senftle

    Single-atom catalysts offer high reactivity and selectivity while maximizing utilization of the expensive active metal component. However, they are susceptible to sintering, where single metal atoms agglomerate into thermodynamically stable clusters. Tuning the binding strength between single metal atoms and oxide supports is essential to prevent sintering. We apply density functional theory, together with a statistical learning approach based on least absolute shrinkage and selection operator regression, to identify property descriptors that predict interaction strengths between single metal atoms and oxide supports. Here, we show that interfacial binding is correlated with readily available physical properties of both the supported metal, such as oxophilicity measured by oxide formation energy, and the support, such as reducibility measured by oxygen vacancy formation energy. These properties can be used to empirically screen interaction strengths between metal–support pairs, thus aiding the design of single-atom catalysts that are robust against sintering.

    更新日期:2018-07-03
  • Branched aldehydes as linchpins for the enantioselective and stereodivergent synthesis of 1,3-aminoalcohols featuring a quaternary stereocentre
    Nat. Catal. Pub Date : 2018-06-25
    Barry M. Trost, Chao-I (Joey) Hung, Tanguy Saget, Elumalai Gnanamani

    The atom-economic conversion of chemical feedstocks into biologically relevant complex molecules in a stereocontrolled fashion remains a continuous challenge to synthetic chemists. In this context, the use of simple ambiphilic starting materials as linchpins allows a bidirectional increase of molecular complexity from widely available precursors. Here, we report the use of branched aldehydes as versatile linchpins for various Zn-ProPhenol-catalysed C–C bond-forming reactions to efficiently construct enantioenriched 1,3-aminoalcohols bearing an acyclic quaternary stereogenic centre. The ability of the Zn-ProPhenol catalyst to selectively activate ambiphilic aldehydes first as nucleophiles for Mannich reactions and then as electrophiles for aldol, Henry and alkyne addition reactions allows for the one-pot synthesis of complex stereotriads from common building blocks. Moreover, this approach can be diastereodivergent by simply selecting the proper catalyst combination. Overall, this catalytic method directly transforms simple and readily available aldehydes into highly functionalized compounds and provides streamlined access to valuable 1,3-aminoalcohols relevant to the synthesis of biologically important molecules.

    更新日期:2018-06-27
  • Complete electron economy by pairing electrolysis with hydrogenation
    Nat. Catal. Pub Date : 2018-06-18
    Rebecca S. Sherbo, Roxanna S. Delima, Valerie A. Chiykowski, Benjamin P. MacLeod, Curtis P. Berlinguette

    Electrosynthesis provides a method of driving organic reaction chemistry under ambient conditions with electricity. Pairing two reactions together enables the synthesis of two valuable chemicals with no waste product. Here we report the paired electrolysis of 4-methoxybenzyl alcohol to 4-methoxybenzaldehyde with the concomitant formation of 1-hexene from 1-hexyne in an electrochemical cell. These reaction chambers are separated by a dense palladium membrane that reduces protons formed at the anode to hydrogen atoms that can permeate through the palladium foil to hydrogenate 1-hexyne. The palladium membrane enables two reactions to be performed in distinct reaction conditions: hydrogenation in organic solvents and electrochemical oxidation in aqueous electrolyte. The starting materials in both chambers react quantitatively over 5 hours of electrolysis, and selectivities ≥95% can be achieved for 4-methoxybenzaldehyde and 1-hexene with control of reaction conditions. Exquisite control of the reaction kinetics and selectivities of each of the individual reactions is demonstrated.

    更新日期:2018-06-19
  • Bridging homogeneous and heterogeneous catalysis by heterogeneous single-metal-site catalysts
    Nat. Catal. Pub Date : 2018-06-12
    Xinjiang Cui, Wu Li, Pavel Ryabchuk, Kathrin Junge, Matthias Beller

    In heterogeneous single-metal-site catalysts (HSMSCs) the active metal centres are located individually on a support and are stabilized by neighbouring surface atoms such as nitrogen, oxygen or sulfur. Modern characterization techniques allow the identification of these individual metal atoms on a given support, and the resulting materials are often referred as single-atom catalysts. Their electronic properties and catalytic activity are tuned by the interaction between the central metal and the neighbouring surface atoms, and their atomically dispersed nature allows for metal utilization of up to 100%. In this way, HSMSCs provide new opportunities for catalysis, and with respect to structure build a bridge between homogeneous and heterogeneous catalysis. Herein, selected publications from 2010 in this area are reviewed and their perspectives for the near future are highlighted. Where appropriate, comparisons between HSMSCs and homogeneous/heterogeneous counterparts are presented.

    更新日期:2018-06-12
  • Chiral heterocycles
    Nat. Catal. Pub Date : 2018-06-12
    Jan-Stefan Völler

    Chiral heterocycles Chiral heterocycles, Published online: 12 June 2018; doi:10.1038/s41929-018-0100-y Chiral heterocycles

    更新日期:2018-06-12
  • Iron-catalysed Suzuki biaryl couplings
    Nat. Catal. Pub Date : 2018-06-12
    Guojiao Wu, Axel Jacobi von Wangelin

    Iron-catalysed Suzuki biaryl couplings Iron-catalysed Suzuki biaryl couplings, Published online: 12 June 2018; doi:10.1038/s41929-018-0096-3 Iron-catalysed Suzuki biaryl couplings

    更新日期:2018-06-12
  • Fe4S4 clusters as small molecule catalysts
    Nat. Catal. Pub Date : 2018-06-12
    Louis Noodleman

    Fe4S4 clusters as small molecule catalysts Fe4S4 clusters as small molecule catalysts, Published online: 12 June 2018; doi:10.1038/s41929-018-0099-0 Iron–sulfur metalloproteins are widespread and efficient catalysts for multielectron reduction of small molecules. Now, research shows that simple Fe4S4 cofactors and related complexes can perform effective reductive chemistry producing small hydrocarbons from CO2 and CO.

    更新日期:2018-06-12
  • Iron-catalysed substrate-directed Suzuki biaryl cross-coupling
    Nat. Catal. Pub Date : 2018-06-12
    Harry M. O’Brien, Mattia Manzotti, Roman D. Abrams, David Elorriaga, Hazel A. Sparkes, Sean A. Davis, Robin B. Bedford

    Although the replacement of ubiquitous palladium catalysts with more sustainable iron-based analogues continues apace, the simple biaryl Suzuki cross-coupling reaction remains stubbornly elusive. It appears that the main issue hampering the reaction is activation of the aryl halide C–X bond. Here we show that a simple N-pyrrole amide and related directing groups on the aryl halide substrates facilitate this process by transient π-coordination to the iron centre. This allows iron-catalysed Suzuki biaryl cross-coupling to proceed, under mild conditions, with alkyllithium-activated aryl pinacol boronic esters.

    更新日期:2018-06-12
  • Aprotic is the key
    Nat. Catal. Pub Date : 2018-06-12
    Marçal Capdevila-Cortada

    Aprotic is the key Aprotic is the key, Published online: 12 June 2018; doi:10.1038/s41929-018-0102-9 Aprotic is the key

    更新日期:2018-06-12
  • Photo-gluing on peptides
    Nat. Catal. Pub Date : 2018-06-12
    Davide Esposito

    Photo-gluing on peptides Photo-gluing on peptides, Published online: 12 June 2018; doi:10.1038/s41929-018-0101-x Photo-gluing on peptides

    更新日期:2018-06-12
  • Recent trends and fundamental insights in the methanol-to-hydrocarbons process
    Nat. Catal. Pub Date : 2018-06-12
    Irina Yarulina, Abhishek Dutta Chowdhury, Florian Meirer, Bert M. Weckhuysen, Jorge Gascon

    The production of high-demand chemical commodities such as ethylene and propylene (methanol-to-olefins), hydrocarbons (methanol-to-hydrocarbons), gasoline (methanol-to-gasoline) and aromatics (methanol-to-aromatics) from methanol—obtainable from alternative feedstocks, such as carbon dioxide, biomass, waste or natural gas through the intermediate formation of synthesis gas—has been central to research in both academia and industry. Although discovered in the late 1970s, this catalytic technology has only been industrially implemented over the past decade, with a number of large commercial plants already operating in Asia. However, as is the case for other technologies, industrial maturity is not synonymous with full understanding. For this reason, research is still intense and a number of important discoveries have been reported over the last few years. In this review, we summarize the most recent advances in mechanistic understanding—including direct C–C bond formation during the induction period and the promotional effect of zeolite topology and acidity on the alkene cycle—and correlate these insights to practical aspects in terms of catalyst design and engineering.

    更新日期:2018-06-12
  • Steering post-C–C coupling selectivity enables high efficiency electroreduction of carbon dioxide to multi-carbon alcohols
    Nat. Catal. Pub Date : 2018-06-11
    Tao-Tao Zhuang, Zhi-Qin Liang, Ali Seifitokaldani, Yi Li, Phil De Luna, Thomas Burdyny, Fanglin Che, Fei Meng, Yimeng Min, Rafael Quintero-Bermudez, Cao Thang Dinh, Yuanjie Pang, Miao Zhong, Bo Zhang, Jun Li, Pei-Ning Chen, Xue-Li Zheng, Hongyan Liang, Wen-Na Ge, Bang-Jiao Ye, David Sinton, Shu-Hong Yu, Edward H. Sargent

    Engineering copper-based catalysts that favour high-value alcohols is desired in view of the energy density, ready transport and established use of these liquid fuels. In the design of catalysts, much progress has been made to target the C–C coupling step; whereas comparatively little effort has been expended to target post-C–C coupling reaction intermediates. Here we report a class of core–shell vacancy engineering catalysts that utilize sulfur atoms in the nanoparticle core and copper vacancies in the shell to achieve efficient electrochemical CO2 reduction to propanol and ethanol. These catalysts shift selectivity away from the competing ethylene reaction and towards liquid alcohols. We increase the alcohol-to-ethylene ratio more than sixfold compared with bare-copper nanoparticles, highlighting an alternative approach to electroproduce alcohols instead of alkenes. We achieve a C2+ alcohol production rate of 126 ± 5 mA cm−2 with a selectivity of 32 ± 1% Faradaic efficiency.

    更新日期:2018-06-12
  • The stability number as a metric for electrocatalyst stability benchmarking
    Nat. Catal. Pub Date : 2018-06-11
    Simon Geiger, Olga Kasian, Marc Ledendecker, Enrico Pizzutilo, Andrea M. Mingers, Wen Tian Fu, Oscar Diaz-Morales, Zhizhong Li, Tobias Oellers, Luc Fruchter, Alfred Ludwig, Karl J. J. Mayrhofer, Marc T. M. Koper, Serhiy Cherevko

    Reducing the noble metal loading and increasing the specific activity of the oxygen evolution catalysts are omnipresent challenges in proton-exchange-membrane water electrolysis, which have recently been tackled by utilizing mixed oxides of noble and non-noble elements. However, proper verification of the stability of these materials is still pending. Here we introduce a metric to explore the dissolution processes of various iridium-based oxides, defined as the ratio between the amounts of evolved oxygen and dissolved iridium. The so-called stability number is independent of loading, surface area or involved active sites and provides a reasonable comparison of diverse materials with respect to stability. The case study on iridium-based perovskites shows that leaching of the non-noble elements in mixed oxides leads to the formation of highly active amorphous iridium oxide, the instability of which is explained by the generation of short-lived vacancies that favour dissolution. These insights are meant to guide further research, which should be devoted to increasing the utilization of highly durable pure crystalline iridium oxide and finding solutions to stabilize amorphous iridium oxides.

    更新日期:2018-06-12
  • Ligand-enabled site-selectivity in a versatile rhodium(ii)-catalysed aryl C–H carboxylation with CO2
    Nat. Catal. Pub Date : 2018-06-04
    Lei Fu, Shangda Li, Zhihua Cai, Yongzheng Ding, Xiao-Qing Guo, Li-Peng Zhou, Daqiang Yuan, Qing-Fu Sun, Gang Li

    Although carbon dioxide (CO2) is an attractive renewable carbon source, its utilization to produce fine chemicals through the catalytic carboxylation of unactivated carbon–hydrogen (C–H) bonds is still very limited and remains a challenge, largely because CO2 is thermodynamically and kinetically stable. In particular, the generation of (hetero)aromatic carboxylic acids via a transition-metal-catalysed C–H carboxylation of arenes with CO2 is extremely rare. Here we report a ligand-enabled site-selective carboxylation of 2-arylphenols under atmospheric pressure of CO2 through a Rh2(OAc)4-catalysed and chelation-assisted C–H bond activation. Remarkably, the reaction occurs selectively on the less nucleophilic phenyl group with the promotion of a phosphine ligand, which overrides the site selectivity dictated by the well-known Kolbe–Schmitt type reaction. The non-acidic C–H bonds within several important classes of heterocycles were also efficiently carboxylated with this method. A mechanistic investigation revealed complexes of active catalysts and that this reaction proceeds under redox-neutral reaction conditions.

    更新日期:2018-06-05
  • Self-sustaining closed-loop multienzyme-mediated conversion of amines into alcohols in continuous reactions
    Nat. Catal. Pub Date : 2018-06-04
    Martina L. Contente, Francesca Paradisi

    The synthesis of alcohols from amine starting materials is an excellent yet challenging strategy for the preparation of pharmaceuticals and polymers. Here we developed a versatile, self-sustaining closed-loop multienzymatic platform for the biocatalytic synthesis of a large range of non-commercially available products in a continuous flow with excellent yields (80 to >99%), reaction times and optical purity of secondary alcohols (>99 enantiomeric excess). This process was also extended to the conversion of biogenic amines into high-value alcohols, such as the powerful antioxidant hydroxytyrosol, and the synthesis of enantiopure 2-arylpropanols via the dynamic kinetic resolution of commercially affordable racemic amines. The system exploits the in situ immobilization of transaminases and redox enzymes which were combined to cater for a fully automated, ultra-efficient synthetic platform with cofactor recycling, in-line recovery of benign by-products and recirculation of the aqueous media that contains the recycled cofactors in catalytic amounts, which increases the efficiency of the system by over 20-fold.

    更新日期:2018-06-05
  • Ambient conversion of CO2 to hydrocarbons by biogenic and synthetic [Fe4S4] clusters
    Nat. Catal. Pub Date : 2018-05-28
    Martin T. Stiebritz, Caleb J. Hiller, Nathaniel S. Sickerman, Chi Chung Lee, Kazuki Tanifuji, Yasuhiro Ohki, Yilin Hu

    The Fe protein of nitrogenase contains a redox active [Fe4S4] cluster that plays a key role in electron transfer and substrate reduction. Here we show that the Fe protein of Methanosarcina acetivorans can reduce CO2 and CO to hydrocarbons under ambient conditions. Further, we demonstrate that this reactivity is inherent to [Fe4S4] clusters, showing the ability of a synthetic [Fe4S4] compound to catalyse the same ambient reaction in solutions. Theoretical calculations suggest a reaction mechanism involving an aldehyde-like intermediate that gives rise to hydrocarbon products upon proton-coupled electron transfer and concomitant removal of water molecules. These results provide a framework for mechanistic investigations of FeS-based activation and reduction of CO2 and CO while facilitating potential development of FeS catalysts capable of ambient conversion of CO2 and CO into fuel products.

    更新日期:2018-05-29
  • Enantioconvergent hydrogenations
    Nat. Catal. Pub Date : 2018-05-21
    Jessica A. Griswold, Jeffrey S. Johnson

    Enantioconvergent hydrogenations Enantioconvergent hydrogenations, Published online: 21 May 2018; doi:10.1038/s41929-018-0073-x The need for new single enantiomer drug substances helps drive the development of new asymmetric catalytic synthetic methods. A new enantioconvergent process enabled by an ionization racemization mechanism allows a hydrogenative route to chiral compounds with two stereocentres.

    更新日期:2018-05-22
  • Boosting the performance of Cu2O photocathodes for unassisted solar water splitting devices
    Nat. Catal. Pub Date : 2018-05-21
    Linfeng Pan, Jin Hyun Kim, Matthew T. Mayer, Min-Kyu Son, Amita Ummadisingu, Jae Sung Lee, Anders Hagfeldt, Jingshan Luo, Michael Grätzel

    Although large research efforts have been devoted to photoelectrochemical (PEC) water splitting in the past several decades, the lack of efficient, stable and Earth-abundant photoelectrodes remains a bottleneck for practical application. Here, we report a photocathode with a coaxial nanowire structure implementing a Cu2O/Ga2O3-buried p–n junction that achieves efficient light harvesting across the whole visible region to over 600 nm, reaching an external quantum yield for hydrogen generation close to 80%. With a photocurrent onset over +1 V against the reversible hydrogen electrode and a photocurrent density of ~10 mA cm−2 at 0 V versus the reversible hydrogen electrode, our electrode constitutes the best oxide photocathode for catalytic generation of hydrogen from sunlight known today. Conformal coating via atomic-layer deposition of a TiO2 protection layer enables stable operation exceeding 100 h. Using NiMo as the hydrogen evolution catalyst, an all Earth-abundant Cu2O photocathode was achieved with stable operation in a weak alkaline electrolyte. To show the practical impact of this photocathode, we constructed an all-oxide unassisted solar water splitting tandem device using state-of-the-art BiVO4 as the photoanode, achieving ~3% solar-to-hydrogen conversion efficiency.

    更新日期:2018-05-22
  • Lithiation-induced amorphization of Pd3P2S8 for highly efficient hydrogen evolution
    Nat. Catal. Pub Date : 2018-05-21
    Xiao Zhang, Zhimin Luo, Peng Yu, Yongqing Cai, Yonghua Du, Daoxiong Wu, Si Gao, Chaoliang Tan, Zhong Li, Minqin Ren, Thomas Osipowicz, Shuangming Chen, Zheng Jiang, Jiong Li, Ying Huang, Jian Yang, Ye Chen, Chung Yen Ang, Yanli Zhao, Peng Wang, Li Song, Xiaojun Wu, Zheng Liu, Armando Borgna, Hua Zhang

    Engineering material structures at the atomic level is a promising way to tune the physicochemical properties of materials and optimize their performance in various potential applications. Here, we show that the lithiation-induced amorphization of layered crystalline Pd3P2S8 activates this otherwise electrochemically inert material as a highly efficient hydrogen evolution catalyst. Electrochemical lithiation of the layered Pd3P2S8 crystal results in the formation of amorphous lithium-incorporated palladium phosphosulfide nanodots with abundant vacancies. The structure change during the lithiation-induced amorphization process is investigated in detail. The amorphous lithium-incorporated palladium phosphosulfide nanodots exhibit excellent electrocatalytic activity towards the hydrogen evolution reaction with an onset potential of −52 mV, a Tafel slope of 29 mV dec−1 and outstanding long-term stability. Experimental and theoretical investigations reveal that the tuning of morphology and structure of Pd3P2S8 (for example, dimension decrease, crystallinity loss, vacancy formation and lithium incorporation) contribute to the activation of its intrinsically inert electrocatalytic property. This work provides a unique way for structure tuning of a material to effectively manipulate its catalytic properties and functionalities.

    更新日期:2018-05-22
  • Iridium-catalysed asymmetric hydrogenation of allylic alcohols via dynamic kinetic resolution
    Nat. Catal. Pub Date : 2018-05-21
    Jianguo Liu, Suppachai Krajangsri, Jianping Yang, Jia-Qi Li, Pher G. Andersson

    Dynamic kinetic resolutions (DKRs) allow for the conversion of both enantiomers of starting material into a single enantiomer of product, hence avoiding the 50% yield limit observed in traditional kinetic resolutions. Transition-metal-catalysed variants have become an important and useful method in asymmetric synthesis. Here we report an asymmetric hydrogenation of allylic alcohols using an Ir–N,P-ligand complex via DKR. In contrast to the many DKRs involving carbonyl reduction, this methodology allows for DKR during alkene reduction. Mechanistic studies support the hypothesis that racemization of the substrate is achieved by cleavage and reforming of the oxygen–carbon bond. Under the cooperative dynamic kinetic asymmetric hydrogenation, a broad range of chiral alcohols containing two stereogenic centres were produced with excellent diastereoselectivities (up to 95:5) and enantioselectivities (up to 99%).

    更新日期:2018-05-22
  • Catalysis makes sweet spirit
    Nat. Catal. Pub Date : 2018-05-11
    Davide Esposito

    Catalysis makes sweet spirit Catalysis makes sweet spirit, Published online: 11 May 2018; doi:10.1038/s41929-018-0086-5 Catalysis makes sweet spirit

    更新日期:2018-05-11
  • Industrial computational catalysis and its relation to the digital revolution
    Nat. Catal. Pub Date : 2018-05-11
    Glenn Jones

    Industrial computational catalysis and its relation to the digital revolution Industrial computational catalysis and its relation to the digital revolution, Published online: 11 May 2018; doi:10.1038/s41929-018-0074-9 Industrial research of new catalysts has benefited from both insight and predictions from first-principles calculations. We now find ourselves on the brink of a digital transformation where multiscale approaches and machine-learning methods promise to revolutionize the field.

    更新日期:2018-05-11
  • Hydrogen from the chalcogen hole
    Nat. Catal. Pub Date : 2018-05-11
    Marçal Capdevila-Cortada

    Hydrogen from the chalcogen hole Hydrogen from the chalcogen hole, Published online: 11 May 2018; doi:10.1038/s41929-018-0089-2 Hydrogen from the chalcogen hole

    更新日期:2018-05-11
  • Evidence of radical chemistry in catalytic methane oxybromination
    Nat. Catal. Pub Date : 2018-05-11
    Vladimir Paunović, Patrick Hemberger, Andras Bodi, Núria López, Javier Pérez-Ramírez

    Unravelling the pathways of catalytic methane functionalization sets the foundations for the efficient production of valuable chemicals and fuels from this abundant feedstock. The catalytic oxybromination of methane into platform compounds bromomethane and dibromomethane constitutes a prominent example, although it displays a puzzling reaction network that has been speculated to involve free-radical intermediates. Here, photoelectron photoion coincidence spectroscopy with synchrotron radiation was used to provide evidence of the evolution of gaseous methyl and bromine radicals over (VO)2P2O7 and EuOBr catalysts and the strong correlation between the formation of methyl radicals and the production of bromomethanes. Complemented by kinetic data on methane oxybromination and non-catalytic methane bromination, these results imply the surface-catalysed generation of bromine radicals and molecular bromine followed by the gas-phase methane bromination, which is rationalized by density functional theory calculations. The findings emphasize the role of both surface and gas-phase steps in halogen-mediated C–H bond activation over heterogeneous catalysts.

    更新日期:2018-05-11
  • Cross-coupling ketones
    Nat. Catal. Pub Date : 2018-05-11
    Enda Bergin

    Cross-coupling ketones Cross-coupling ketones, Published online: 11 May 2018; doi:10.1038/s41929-018-0087-4 Cross-coupling ketones

    更新日期:2018-05-11
  • Easy alloying on flat carbides
    Nat. Catal. Pub Date : 2018-05-11
    Wilfred T. Tysoe

    Easy alloying on flat carbides Easy alloying on flat carbides, Published online: 11 May 2018; doi:10.1038/s41929-018-0075-8 Reactive metal–support interactions are generally considered characteristic of oxide supports. Now, two-dimensional niobium carbide, a member of the MXenes family, has been used as a platinum support providing an active water-gas shift catalyst via reduction-induced formation of stable, catalytically active Nb–Pt nanoparticles.

    更新日期:2018-05-11
  • Catalytic chemoselective functionalization of methane in a metal−organic framework
    Nat. Catal. Pub Date : 2018-05-11
    Xuan Zhang, Zhiyuan Huang, Magali Ferrandon, Dali Yang, Lee Robison, Peng Li, Timothy C. Wang, Massimiliano Delferro, Omar K. Farha

    Methane constitutes the largest fraction of natural gas reserves and is a low-cost abundant starting material for the synthesis of value-added chemicals and fuel. Selective catalytic functionalization of methane remains a vital goal in the chemical sciences due to its low intrinsic reactivity. Borylation has recently emerged as a promising route for the catalytic functionalization of methane. A major challenge in this regard is selective borylation towards the monoborylated product that is more active than methane and can easily lead to over-functionalization. Herein, we report a highly selective microporous metal−organic-framework-supported iridium(iii) catalyst for methane borylation that exhibits a chemoselectivity of >99% (mono versus bis at 19.5% yield; turnover number = 67) for monoborylated methane, with bis(pinacolborane) as the borylation reagent in dodecane, at 150 °C and 34 atm of methane. The preference for the monoborylated product is ascribed to the shape-selective effect of the metal−organic framework pore structures.

    更新日期:2018-05-11
  • Coming together
    Nat. Catal. Pub Date : 2018-05-11

    Coming together Coming together, Published online: 11 May 2018; doi:10.1038/s41929-018-0088-3 Historically catalysis has evolved as a set of different fields linked together by a unifying concept. While the distinctions between the various areas serve a purpose, exciting work is happening at the interfaces.

    更新日期:2018-05-11
  • Reactive metal–support interactions at moderate temperature in two-dimensional niobium-carbide-supported platinum catalysts
    Nat. Catal. Pub Date : 2018-05-07
    Zhe Li, Yanran Cui, Zhenwei Wu, Cory Milligan, Lin Zhou, Garrett Mitchell, Biao Xu, Enzheng Shi, Jeffrey T. Miller, Fabio H. Ribeiro, Yue Wu

    The reactive metal–support interaction (RMSI) offers electronic, geometric and compositional effects that can be used to tune catalytic active sites. Generally, supports other than oxides are disregarded as candidates for RMSI. Here, we report an example of non-oxide-based RMSI between platinum and Nb2CT x MXene—a recently developed, two-dimensional metal carbide. The surface functional groups of the two-dimensional carbide can be reduced, and a Pt–Nb surface alloy is formed at a moderate temperature (350 °C). Such an alloy exhibits weaker CO adsorption than monometallic platinum. Water-gas shift reaction kinetics reveals that the RMSI stabilizes the nanoparticles and creates alloy–MXene interfaces with higher H2O activation ability compared with a non-reducible support or a bulk niobium carbide. This RMSI between platinum and the niobium MXene support can be extended to other members of the MXene family and opens new avenues for the facile design and manipulation of functional bimetallic catalysts.

    更新日期:2018-05-08
  • Streamlined hydrogen production from biomass
    Nat. Catal. Pub Date : 2018-04-30
    Ping Zhang, Yan-Jun Guo, Jianbin Chen, Yu-Rou Zhao, Jun Chang, Henrik Junge, Matthias Beller, Yang Li

    Hydrogen is playing an increasingly larger role in clean energy technologies and the emerging hydrogen economy. However, efficient and selective H2 production from renewable resources is rare so far. Herein, we describe a dehydrogenation route that is applicable to various kinds of non-food-related biomass and daily waste, such as wheat straw, corn straw, rice straw, reed, bagasse, bamboo sawdust, cardboard and newspaper. H2 yields up to 95% were achieved by a one-pot, two-step reaction with a 69 ppm molecularly defined iridium catalyst bearing an imidazoline moiety from formic acid, which was in turn obtained via a 1 v% dimethyl sulfoxide-promoted hydrolysis–oxidation of biomass. Formation of the unwanted side products CO and CH4 was no more than 22 and 2 ppm, respectively, while CO2 was captured as carbonate. The resulting hydrogen gas can be directly applied in proton exchange membrane fuel cells.

    更新日期:2018-04-30
  • A universal principle for a rational design of single-atom electrocatalysts
    Nat. Catal. Pub Date : 2018-04-30
    Haoxiang Xu, Daojian Cheng, Dapeng Cao, Xiao Cheng Zeng

    Developing highly active single-atom catalysts for electrochemical reactions is a key to future renewable energy technology. Here we present a universal design principle to evaluate the activity of graphene-based single-atom catalysts towards the oxygen reduction, oxygen evolution and hydrogen evolution reactions. Our results indicate that the catalytic activity of single-atom catalysts is highly correlated with the local environment of the metal centre, namely its coordination number and electronegativity and the electronegativity of the nearest neighbour atoms, validated by available experimental data. More importantly, we reveal that this design principle can be extended to metal–macrocycle complexes. The principle not only offers a strategy to design highly active nonprecious metal single-atom catalysts with specific active centres, for example, Fe-pyridine/pyrrole-N4 for the oxygen reduction reaction; Co-pyrrole-N4 for the oxygen evolution reaction; and Mn-pyrrole-N4 for the hydrogen evolution reaction to replace precious Pt/Ir/Ru-based catalysts, but also suggests that macrocyclic metal complexes could be used as an alternative to graphene-based single-atom catalysts.

    更新日期:2018-04-30
  • Growing highly pure semiconducting carbon nanotubes by electrotwisting the helicity
    Nat. Catal. Pub Date : 2018-04-23
    Jiangtao Wang, Xiang Jin, Zebin Liu, Guo Yu, Qingqing Ji, Haoming Wei, Jin Zhang, Ke Zhang, Dongqi Li, Zi Yuan, Jiachen Li, Peng Liu, Yang Wu, Yang Wei, Jiaping Wang, Qunqing Li, Lina Zhang, Jing Kong, Shoushan Fan, Kaili Jiang

    Carbon nanotubes (CNTs) are anticipated to be the successor of silicon in next-generation integrated circuits. However, one great challenge to the practical application of this concept is the need to grow horizontal semiconducting CNT arrays with very high purity. Here we show that this roadblock can be eliminated by switching the direction of an applied electric field during synthesis. This electro-renucleation approach twists the chirality of the CNTs to produce nearly defect-free s-CNTs horizontally aligned on the substrate with less than 0.1% residual metallic CNT. In principle, this residual percentage can be further reduced to less than 1 ppm simply by tuning the CNTs’ diameters to around 1.3 nm. Electro-renucleation thus offers a potential pathway to practical applications of CNT electronics and opens up a new avenue for large-scale selective synthesis of semiconducting CNTs and other nanomaterials.

    更新日期:2018-04-23
  • Mechanochemistry breaks with expectations
    Nat. Catal. Pub Date : 2018-04-16
    Jörg Weissmüller

    Mechanochemistry breaks with expectations Mechanochemistry breaks with expectations, Published online: 16 April 2018; doi:10.1038/s41929-018-0061-1 Tensile strain of a solid surface can result in either strengthening or weakening of bonds with adsorbates. Adsorption energies of different adsorbate/site combinations may be shifted in different directions — a striking violation of the Brønsted–Evans–Polanyi relation.

    更新日期:2018-04-16
  • Light on the path
    Nat. Catal. Pub Date : 2018-04-16
    Ashwathi Iyer, Elif Ertekin

    Light on the path Light on the path, Published online: 16 April 2018; doi:10.1038/s41929-018-0058-9 Discerning the precise mechanisms of photocatalytic energy conversion has long been a challenge. A computational multiscale approach reveals insights into the reaction pathways and rate-limiting steps of the oxygen evolution reaction, the bottleneck for water splitting on TiO2 surfaces.

    更新日期:2018-04-16
  • Arenes and amines
    Nat. Catal. Pub Date : 2018-04-16
    Enda Bergin

    Arenes and amines Arenes and amines, Published online: 16 April 2018; doi:10.1038/s41929-018-0064-y Arenes and amines

    更新日期:2018-04-16
  • Ensuring reproducibility in computational catalysis
    Nat. Catal. Pub Date : 2018-04-16

    Ensuring reproducibility in computational catalysis Ensuring reproducibility in computational catalysis, Published online: 16 April 2018; doi:10.1038/s41929-018-0068-7 Reproducibility is a cornerstone of science. It is imperative that everyone involved in the generation of scientific knowledge holds themself to the highest standard to ensure reproducibility.

    更新日期:2018-04-16
  • Identifying the key obstacle in photocatalytic oxygen evolution on rutile TiO2
    Nat. Catal. Pub Date : 2018-04-16
    Dong Wang, Tian Sheng, Jianfu Chen, Hai-Feng Wang, P. Hu

    As the bottleneck in photocatalytic water splitting, the oxygen evolution reaction (OER) has drawn huge attention, but its efficiency still falls short of expectations. A widely accepted speculation is that the catalysts’ activity is insufficient (high reaction barriers need to be overcome). Here, we develop a first-principles method to investigate the photocatalytic OER at the water/TiO2(110) interface. A full mechanism uncovering the importance of radicals is determined. Kinetic analysis further enables to quantitatively estimate each possible obstacle in the process. We demonstrate unambiguously that the rate-determining factor of the OER varies with the concentration of surface-reaching photoholes (Ch+). Under experimental conditions, the intrinsic catalytic activity of TiO2(110) does not represent the main obstacle, but all steps involving the photoholes are slow due to their low concentrations. This suggests that the key to enhance the OER efficiency is to increase Ch+ before Ch+ reaches the estimated threshold (Ch+ = ~10−4).

    更新日期:2018-04-16
  • An eye on surface changes
    Nat. Catal. Pub Date : 2018-04-16
    Alexis Grimaud

    An eye on surface changes An eye on surface changes, Published online: 16 April 2018; doi:10.1038/s41929-018-0059-8 For electrocatalysts, the activity and stability is determined by the surface — often just a few atomic layers thick. Now atom probe tomography is used to examine the changing surface of an oxygen evolution catalyst at near-atomic-scale resolution, linking structure to activity and stability.

    更新日期:2018-04-16
  • Catalysing surface film formation
    Nat. Catal. Pub Date : 2018-04-16
    Harry E. Hoster

    Catalysing surface film formation Catalysing surface film formation, Published online: 16 April 2018; doi:10.1038/s41929-018-0060-2 The solid electrolyte interphase that forms on graphite anodes plays a vital role in the performance of lithium-ion batteries. Now research shows that the formation of lithium fluoride deposits — one of the main components of the solid electrolyte interphase — is strongly influenced by the electrocatalytic activity of the anode.

    更新日期:2018-04-16
  • Small temperature changes matter
    Nat. Catal. Pub Date : 2018-04-16
    Jan-Stefan Völler

    Small temperature changes matter Small temperature changes matter, Published online: 16 April 2018; doi:10.1038/s41929-018-0066-9 Small temperature changes matter

    更新日期:2018-04-16
  • Electrocatalytic transformation of HF impurity to H2 and LiF in lithium-ion batteries
    Nat. Catal. Pub Date : 2018-04-09
    Dusan Strmcnik, Ivano E. Castelli, Justin G. Connell, Dominik Haering, Milena Zorko, Pedro Martins, Pietro P. Lopes, Bostjan Genorio, Thomas Østergaard, Hubert A. Gasteiger, Filippo Maglia, Byron K. Antonopoulos, Vojislav R. Stamenkovic, Jan Rossmeisl, Nenad M. Markovic

    The formation of solid electrolyte interphase on graphite anodes plays a key role in the efficiency of Li-ion batteries. However, to date, fundamental understanding of the formation of LiF as one of the main solid electrolyte interphase components in hexafluorophosphate-based electrolytes remains elusive. Here, we present experimental and theoretical evidence that LiF formation is an electrocatalytic process that is controlled by the electrochemical transformation of HF impurity to LiF and H2. Although the kinetics of HF dissociation and the concomitant production of LiF and H2 is dependent on the structure and nature of surface atoms, the underlying electrochemistry is the same. The morphology, and thus the role, of the LiF formed is strongly dependent on the nature of the substrate and HF inventory, leading to either complete or partial passivation of the interface. Our finding is of general importance and may lead to new opportunities for the improvement of existing, and design of new, Li-ion technologies.

    更新日期:2018-04-10
  • Foundations and strategies of the construction of hybrid catalysts for optimized performances
    Nat. Catal. Pub Date : 2018-04-09
    Rong Ye, Jie Zhao, Brent B. Wickemeyer, F. Dean Toste, Gabor A. Somorjai

    Catalysts are generally classified into three categories: homogeneous, heterogeneous and enzyme, each evolved as an independent field. Efforts to bridge these fields are scarce but desirable. In this Perspective, we first describe how numerous classes of reactions can be achieved by all three categories of catalysts. Examples are given based on a selective survey of the literature. Next, a selection of important approaches, the benefits and challenges of constructing heterogeneous–homogeneous, heterogeneous–enzyme and homogeneous–enzyme hybrid catalysts are discussed based on published researches. Hybrid catalysts not only increase the performance, including activity, selectivity, lifetime and recyclability compared to one of the components, but also offer extra functions such as a microenvironment for different reaction pathways, and cascade catalysis for products that are challenging to produce. We expect future tailor-made hybrid catalysts will combine the advantages of the components and be optimized for industrial applications.

    更新日期:2018-04-10
  • Complex dynamics in a two-enzyme reaction network with substrate competition
    Nat. Catal. Pub Date : 2018-04-09
    Yifei Zhang, Stanislav Tsitkov, Henry Hess

    Enzymatic reaction networks capable of generating complex spatiotemporal dynamics are not only the basis of essential biological processes, but also the basic units of synthetic systems with autonomous, adaptive and programmable behaviours. Activation and inhibition have been usually considered as indispensable interactions for the construction of such networks. Here we present an enzymatic reaction network that consists of a flavin adenine dinucleotide-dependent oxidoreductase and a peroxidase that can generate tunable complex dynamics. These include charging/discharging, rectangular and parabolic pulses in a closed system, which are based on delayed and self-adapting substrate competition, rather than on activation or inhibition. Additionally, this system can spontaneously form visible spatiotemporal patterns that arise from reaction-driven Rayleigh–Bénard convection. This work demonstrates that substrate competition could be an alternative path towards constructing biochemical networks with complex dynamics.

    更新日期:2018-04-10
  • Overcoming ammonia synthesis scaling relations with plasma-enabled catalysis
    Nat. Catal. Pub Date : 2018-04-02
    Prateek Mehta, Patrick Barboun, Francisco A. Herrera, Jongsik Kim, Paul Rumbach, David B. Go, Jason C. Hicks, William F. Schneider

    Correlations between the energies of elementary steps limit the rates of thermally catalysed reactions at surfaces. Here, we show how these limitations can be circumvented in ammonia synthesis by coupling catalysts to a non-thermal plasma. We postulate that plasma-induced vibrational excitations in N2 decrease dissociation barriers without influencing subsequent reaction steps. We develop a density-functional-theory-based microkinetic model to incorporate this effect, and parameterize the model using N2 vibrational excitations observed in a dielectric-barrier-discharge plasma. We predict plasma enhancement to be particularly great on metals that bind nitrogen too weakly to be active thermally. Ammonia synthesis rates observed in a dielectric-barrier-discharge plasma reactor are consistent with predicted enhancements and predicted changes in the optimal metal catalyst. The results provide guidance for optimizing catalysts for application with plasmas.

    更新日期:2018-04-03
  • Atomic-scale insights into surface species of electrocatalysts in three dimensions
    Nat. Catal. Pub Date : 2018-03-26
    T. Li, O. Kasian, S. Cherevko, S. Zhang, S. Geiger, C. Scheu, P. Felfer, D. Raabe, B. Gault, K. J. J. Mayrhofer

    The topmost atomic layers of electrocatalysts determine the mechanism and kinetics of reactions in many important industrial processes, such as water splitting, chlor-electrolysis or fuel cells. Optimizing the performance of electrocatalysts requires a detailed understanding of surface-state changes during the catalytic process, ideally at the atomic scale. Here, we use atom probe tomography to reveal the three-dimensional structure of the first few atomic layers of electrochemically grown iridium oxide, an efficient electrocatalyst for the oxygen evolution reaction. We unveil the formation of confined, non-stoichiometric Ir–O species during oxygen evolution. These species gradually transform to IrO2, providing improved stability but also a decrease in activity. Additionally, electrochemical growth of oxide in deuterated solutions allowed us to trace hydroxy-groups and water molecules present in the regions of the oxide layer that are favourable for the oxygen evolution and iridium dissolution reactions. Overall, we demonstrate how tomography with near-atomic resolution advances the understanding of complex relationships between surface structure, surface state and function in electrocatalysis.

    更新日期:2018-03-26
  • Efficient hydrogen peroxide generation using reduced graphene oxide-based oxygen reduction electrocatalysts
    Nat. Catal. Pub Date : 2018-03-26
    Hyo Won Kim, Michael B. Ross, Nikolay Kornienko, Liang Zhang, Jinghua Guo, Peidong Yang, Bryan D. McCloskey

    Electrochemical oxygen reduction has garnered attention as an emerging alternative to the traditional anthraquinone oxidation process to enable the distributed production of hydrogen peroxide. Here, we demonstrate a selective and efficient non-precious electrocatalyst, prepared through an easily scalable mild thermal reduction of graphene oxide, to form hydrogen peroxide from oxygen. During oxygen reduction, certain variants of the mildly reduced graphene oxide electrocatalyst exhibit highly selective and stable peroxide formation activity at low overpotentials (<10 mV) under basic conditions, exceeding the performance of current state-of-the-art alkaline catalysts. Spectroscopic structural characterization and in situ Raman spectroelectrochemistry provide strong evidence that sp2-hybridized carbon near-ring ether defects along sheet edges are the most active sites for peroxide production, providing new insight into the electrocatalytic design of carbon-based materials for effective peroxide production.

    更新日期:2018-03-26
  • The magic of triads
    Nat. Catal. Pub Date : 2018-03-08
    Malte Behrens

    The magic of triads The magic of triads, Published online: 08 March 2018; doi:10.1038/s41929-018-0038-0 Ammonia synthesis is an energy-intensive process due to the high activation barrier for N2 dissociation, which is the rate-determining step on conventional catalysts. Now, a ternary intermetallic catalyst is reported to be capable of catalysing this reaction through an alternative pathway.

    更新日期:2018-03-08
  • Chemoenzymatic asymmetric synthesis of the metallo-β-lactamase inhibitor aspergillomarasmine A and related aminocarboxylic acids
    Nat. Catal. Pub Date : 2018-03-08
    Haigen Fu, Jielin Zhang, Mohammad Saifuddin, Gea Cruiming, Pieter G. Tepper, Gerrit J. Poelarends

    Metal-chelating aminocarboxylic acids are being used in a broad range of domestic products and industrial applications. With the recent identification of the fungal natural product aspergillomarasmine A as a potent and selective inhibitor of metallo-β-lactamases and a promising co-drug candidate to fight antibiotic-resistant bacteria, the academic and industrial interest in metal-chelating chiral aminocarboxylic acids further increased. Here, we report a biocatalytic route for the asymmetric synthesis of aspergillomarasmine A and various related aminocarboxylic acids from retrosynthetically designed substrates. This synthetic route highlights a highly regio- and stereoselective carbon–nitrogen bond-forming step catalysed by ethylenediamine-N,N′-disuccinic acid lyase. The enzyme shows broad substrate promiscuity, accepting a wide variety of amino acids with terminal amino groups for selective addition to fumarate. We also report a two-step chemoenzymatic cascade route for the rapid diversification of enzymatically prepared aminocarboxylic acids by N-alkylation in one pot. This biocatalytic methodology offers a useful alternative route to difficult aminocarboxylic acid products.

    更新日期:2018-03-08
Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
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