Abstract The green and nano catalyst was simply prepared through the reaction of ferric sulfasalazine with nanomaterial CoFe2O4-cellulose as a magnetic biopolymer surface. This novel heterogeneous organometallic catalyst was characterized by X-ray diffraction, field emission scanning electron microscopy, FT-IR spectroscopy, thermal gravimetric analysis, and energy dispersive analysis of X-rays, and inductively coupled plasma-mass spectrometry. This green sulfasalazine drug complex supported on CoFe2O4 cellulose was applied as an efficient and recyclable catalyst for organic reactions such as synthesis of functionalized 4H- pyrans and 1,4-dihydropyridines derivatives. All of the reactions were carried out successfully under mild conditions in a short reaction time. The used catalyst was easily separated and reused for 6 runs without noticeable loss of its catalytic activity. Graphic Abstract

Abstract Precipitated iron catalysts containing structural promoters were prepared and their Fischer–Tropsch synthesis (FTS) performance was tested under the same reaction condition. BET, XRD, H2-TPR, and MES were conducted to characterize the phases, structure, morphology, reducibility and carbonization characteristics of the catalysts. It was observed that the reduced catalysts under syngas(H2/CO = 5) promoted with Al/Zr generate more Fe5C2 phase than Si/Ti, which showed that Al/Zr promoted catalysts are more easily reduced than the Si/Ti promoted ones. Addition of Zr and Al promoters improved the reduction and carbonization process of iron-based FTS catalysts. FTS performance data showed that the addition of Al and Zr can increase the CO hydrogenation activity compared to Si and Ti. Moreover, these two promoted catalysts also exhibited excellent stability. Graphic Abstract

The application of enzymes presents a great advantage regarding highly selective reactions; however, it involves also challenges due to their sensitivity. Immobilization offers one strategy to overcome those challenges enabling enzyme stabilization, as well as retention. In the present study, covalent attachment on hydrophilic amino‐functionalized carriers is found to be the most promising immobilization method for the investigated reaction system. To achieve this, a novel method for preparation of silica particles with subsequent amino‐functionalization is developed to prepare spherical carriers for enzyme immobilization, whereby high porosities are obtained based on polymerization. With these particles, immobilization of an alcohol dehydrogenase and a formate dehydrogenase is realized with residual activities of 70% and 80% after 12 consecutive batches, respectively. The two immobilized enzymes are used in the reduction of cinnamyl aldehyde with in situ cofactor regeneration, obtaining a conversion of 100% and up to 10‐fold higher turnover numbers compared to the free enzyme.

A combined catalyst comprising TiO2‐supported Re (Re(1)/TiO2; Re = 1 wt%) and H‐MOR (SiO2/Al2O3 = 90) was found to promote the methylation of benzene using CO2 and H2. This catalytic system exhibited high performance with regard to the synthesis of methylated benzenes and gave high yields of total methylated products (up to 52% benzene‐based yield and 42% CO2‐based yield) under the reaction conditions employed in this study (pCO2 = 1 MPa; pH2 = 5 MPa; T = 250 °C; t = 20 h) in a batch reactor. Catalyst screening demonstrated that a combination of Re(1)/TiO2 and H‐MOR (SiO2/Al2O3 = 90) exhibited superior performance compared to other combinations of supported metal catalysts and zeolites in terms of both yield and selectivity for methylated benzenes.

The physicochemical properties of heterogeneous catalysts in static or inert environments often deviate greatly from the properties under in‐situ or working conditions. To gain an insightful understanding of realistic catalyst properties and the corresponding catalytic mechanisms, it is essential to identify and rationalize changes in catalysts under reaction conditions. In recent years, in‐situ transmission electron microscope (in‐situ TEM) techniques have been increasingly developed, offering a unique approach to visualize the evolution of heterogeneous catalysis with ultra‐high spatial resolution, good energy resolution and reasonable temporal resolution under controllable or even realistic catalytic conditions. In this review, we have summarized recent advances in the in‐situ TEM analysis of heterogeneous catalysis, which suggests the great potential of this technique in this important field. Furthermore, technical challenges and possible solutions are discussed.

Conversing CO2 into value‐added chemicals endows electrochemical CO2 reduction reaction (CO2RR) with the potential to tackle over issues induced by the increased CO2 level in the atmosphere. The associated technological viability of this process is highly dependent on exploring efficient electrocatalysts. In this work, we successfully synthesized nitrogen and sulfur co‐doped carbon nanosheets (NS‐CNSs), which are comprehensively characterized by a variety of characterization techniques. When used as the catalyst for CO2RR, the NS‐CNSs exhibit remarkably high catalytic activity and selectivity with a faradaic efficiency of ~85.4% for CO production and long‐term durability. The superior performance of this material majorly originates from the unique nanosheets structure with large porosity and the co‐doped S and N in the nanosheets, which exposed larger electrochemical activity surface areas and more active sites for promoting CO2 reduction.

Pr 2 O 3 supported Ru nanolayers and Ru nanoparticles catalysts were examined for the synthesis of quinolines. The Ru nanolayer was most active catalyst and showed a broad substrate scope. Structure‐activity relationship demonstrated that the metallic state and morphology of Ru as well as the basic site of Pr 2 O 3 were indispensable factors of this catalytic system.

Abstract An important decrease in the soot combustion temperature was observed by employing potassium and manganese on ZrO2 as support; significantly boosted soot combustion was obtained with the K/ZrO2 and Mn–K/ZrO2 catalysts for T50 at 295 and 240 °C, respectively. The enhanced catalytic activity by using the Mn–K/ZrO2 catalyst could be attributed to the alkaline metal ion, which improved the catalyst/soot contact. XPS results revealed the presence of surface vacancies, where the addition of manganese improved the lattice oxygen and concentration of OH groups on the Mn–K/ZrO2 catalyst at low temperatures; the presence of surface vacancies was facilitated by the interaction between potassium and manganese. The Mn–K/ZrO2 catalyst showed resistance to deactivation for five cycles.

Abstract Pt catalysts supported on the commonly used supports Al2O3, SiO2 and on mesostructured silicates SBA-15 and MCM-48 were examined in the dehydrogenation of decalin, that is the promising liquid organic hydrogen carrier (LOHC). Synthesized catalysts were studied by low-temperature nitrogen adsorption, temperature programmed reduction, high-resolution transmission electron microscopy. The catalysts are characterized by various dispersion of platinum. The activity of catalysts in decalin dehydrogenation decreases in the following order Pt/MCM-48 > Pt/SBA-15 > Pt/SiO2 > Pt/Al2O3. Pt/MCM-48 catalyst allows to release hydrogen in the decalin amount of 5.7 wt% and can be considered the promising LOHC hydrogen storage technology. Graphic Abstract

Abstract Heavy crude oil enhanced into a lighter oil by hydrocracking process with nickel nanoparticles (Ni NPs) as catalysts. Ni NPs were synthesized by colloidal method (chemical reduction of metal salts). The reduction of nickel nitrate hexahydrate ((Ni(NO3)2·6H2O) was done using sodium borohydride (NaBH4) as a reducing agent in presence of polyvinylpyrrolidone which worked as a protective and stabilizing agent; ethanol was used as a solvent. The properties of the nanoparticles were investigated by FT-IR, TEM, XRD, and HRTEM. These techniques confirmed the formation of Ni NPs with an average size of 10 nm and a tetragonal structure. The experiments were carried out in a batch reactor at 45 Kgf cm−2 (initial H2 pressure), 380 °C, stirring speed of 500 rpm and reaction time of 1 h. In all cases, the increase in the concentration of Ni nanoparticles improved the physical and chemical properties of heavy crude oil, even in limited hydrogen conditions; these properties were measured in terms of viscosity, SARA analysis, sulfur and nitrogen removal, and chromatographic analysis of gaseous products. The asphaltenes conversion was of 26.31% and moderate sulfur removal was achieved, these results are promising for EOR application. Graphic Abstract

Abstract In this work, Zn/ZnO composite photocatalyst was successfully synthesized by simple hydrothermal method. Photocurrent test shows that the presence of Zn can effectively improve the light response of composites. Electrochemical impedance spectroscopy indicates that Zn/ZnO has higher point and separation efficiency and faster carrier transmission. Degradation tests of methyl orange showed that Zn/ZnO had higher degradation efficiency than commercial ZnO. In the same time, Zn/ZnO can degrade nearly 90% of methyl orange, while commercial zinc oxide has less than 10%. Meanwhile, the photocatalyst synthesized in the test of photocatalytic removal of NO also shows higher photocatalytic activity. Compared with commercial ZnO, which removed 48% of NO in 20 min, Zn/ZnO could remove 74% of NO in 8 min, and NO will be further oxidized to NO3− after being oxidized to NO2, which can effectively reduce secondary pollution in the reaction process. These results indicate that Zn/ZnO composite photocatalysts have high photocatalytic activity in both solid–liquid and gas–solid systems. Graphic Abstract Photodegradation of MO (a), and NO removal (b) photocatalytic mechanism of Zn/ZnO under irradiation.

With the aim of preparing bio‐sourced supports with enhanced properties in catalysis, we devised an original strategy allowing the immobilization of metal nanoparticles. Thus, size‐controlled hydrochars with a high degree of hydroxyl functionalities, from both neat sucrose or modified with acrylic acid (10 wt. %), were derivatized with ether linkers containing ammonium groups. These non‐porous carbon‐based materials were used as suitable supports for the immobilization of palladium nanoparticles. The catalytic materials were synthesized by reduction of Pd(OAc) 2 to Pd(0) under H 2 atmosphere in the presence of the corresponding hydrochar, and fully characterized by standard methods. Among the different hydrochar‐supported palladium materials, those functionalized with tetraalkylammonium groups afforded heterogeneous catalysts, exhibiting high activity in hydrogenations of different types of substrates (alkynes, alkenes, and carbonyl and nitro derivatives). The most efficient catalyst was recycled up to ten runs without loss of catalytic behavior, in agreement with the unchanged catalytic materials after catalysis [Transmission Electron Microscopy (TEM) analyses] and the lack of metal leaching in the extracted organic [no palladium detected by Inductively Coupled Plasma‐Atomic Emission Spectrometry (ICP‐AES)]; these systems exhibited enhanced recyclability properties as compared to commercial Pd/C catalyst.

We report a thermally stable multilayered two‐dimensional vanadium carbide (V 2 CT x ) MXenes catalyst for the direct conversion of methane (CH 4 ) into benzene (C 6 H 6 ). The multilayered carbide structure shows state‐of‐the‐art CH 4 conversion 11.8% with a C 6 H 6 formation rate of 1.9 mmol g cat ‐1 h ‐1 (4.84% C 6 H 6 yield) at 700 0 C, which is comparable to the benchmark Mo/ZSM‐5 catalyst. The structure‐activity relationship was explored by numerous characterization techniques including in‐situ/operando Raman‐MS, ex‐situ X‐ray diffraction (XRD), scanning electron microscopy (SEM), X‐ray photoelectron spectroscopy (XPS), and ammonia temperature programmed desorption (NH 3 ‐TPD). This work provides a new platform to design and explore multilayered two‐dimensional catalysts demonstrating confinement effect to convert CH 4 into *C 2 H 3 intermediates which further oligomerizes inside multilayered structures producing C 6 H 6 as a final product.

Manganese (Mn) nitrides are important nitrogen (N) carriers for small‐scale intermittent ammonia (NH 3 ) synthesis. However, only 3~8% of lattice N are converted into NH 3 . In this study, the geometric and electronic structures of well‐defined Mn 4 N and Mn 2 N lattices were altered using transition metal heteroatoms (Cr, Fe, Co, Ni, Mo) to understand the driving force behind lattice N diffusion and extraction. Density Functional Theory (DFT) revealed that the binding of early hydrogenation product (NH) follows a linear relationship with lattice N over a wide range of close‐packed surfaces. But, the binding of NH 2 and NH 3 are more sensitive to the geometric and electronic structures. Further, the chemical bonding can be quantitatively characterized with the covalency derived from Crystal Orbital Hamiltonian Population (COHP). In the Eley Rideal‐Mars van Krevelan pathway, the overall NH 3 formation free energy (ΔE NH3 ) and lattice N diffusion barrier (E a ) are the respective thermodynamic and kinetic determining factors. Aided by a rate‐determining step (RDS) model, Mn 4 N modified with Fe, Co, Ni single‐atom dopants all show enhanced rates for NH 3 formation.

In this work the patent landscape of catalytic hydrogenation reactions was evaluated with the aid of the online database Patbase®. The respective classifications were used to distinguish the development of trends among patents. The findings give a detailed picture of the patent activity on the field of hydrogenation catalysis and may give the user information on technological areas that occur more often in the patent literature than others.

Compared with biocatalysis in aqueous media, the use of enzymes in neat organic solvents enables increased solubility of hydrophobic substrates and can lead to more favorable thermodynamic equilibria, avoidance of possible hydrolytic side reactions and easier product recovery. ω‐Transaminases from Arthrobacter sp. (AsR‐ωTA) and Chromobacterium violaceum (Cv‐ωTA) were immobilized on controlled porosity glass metal‐ion affinity beads (EziG) and applied in neat organic solvents for the amination of 1‐phenoxypropan‐2‐one with 2‐propylamine. The reaction system was investigated in terms of type of carrier material, organic solvents and reaction temperature. Optimal conditions were found with more hydrophobic carrier materials and toluene as reaction solvent. The system’s water activity (αw) was controlled via salt hydrate pairs during both the biocatalyst immobilization step and the progress of the reaction in different non‐polar solvents. Notably, the two immobilized ωTAs displayed different optimal values of αw, namely 0.7 for EziG3‐AsR‐ωTA and 0.2 for EziG3‐Cv‐ωTA. In general, high catalytic activity was observed in various organic solvents even when a high substrate concentration (450‐550 mM) and only one equivalent of 2‐propylamine were applied. Under batch conditions, a chemical turnover (TTN) above 13000 was obtained over four subsequent reaction cycles with the same batch of EziG‐immobilized ωTA. Finally, the applicability of the immobilized biocatalyst in neat organic solvents was further demonstrated in a continuous flow packed‐bed reactor. The flow reactor showed excellent performance without observable loss of enzymatic catalytic activity over several days of operation. In general, ca. 70% conversion was obtained in 72 hours using a 1.82 mL flow reactor and toluene as flow solvent, thus affording a space‐time yield of 1.99 g L‐1 h‐1. Conversion reached above 90% when the reaction was run up to 120 hours.

Tandem catalysis, the use of a single catalyst to promote two or more mechanistically distinct cycles in one pot to assemble complex organic molecules, is an attractive target. In this paper, we report a reductant‐triggered tandem palladium catalysis process that rapidly assembles 3,4‐fused tricyclic indoles from three readily available starting materials. This tandem process involves a Pd0‐catalyzed in situ coupling/cyclization/Michael addition reaction to install simultaneously two functional groups at the C4 and the C3 positions of indoles. This is followed by a Pd0‐catalyzed intramolecular cyclization which builds a seven‐membered C4, C3‐bridge. Sodium formate is used to trigger the necessary switching between the palladium catalysed reactions.

A cascade procedure for the efficient and atom‐economical synthesis of spiro[5.n (n = 6‐8)]heterocycles has been developed. This process goes through the tandem reactions of base‐promoted ring‐expansion of cyclic ketones followed by Cu‐catalyzed intramolecular C‐2 spirocyclization of indoles. Easily accessible starting materials and broad substrate scope are the advantaged features of this protocol.

An organocatalyst‐controlled site‐selectivity switchable enantioselective Friedel‐Crafts reaction of unprotected 1‐naphthols has been established for the first time via the conjugate addition of 1‐azadienes. By two chiral complementary squaramide and phosphoric acid, both ortho‐ and para‐selective Friedel‐Crafts alkylations of 1‐naphthols were independently achieved with high efficiency and enantioselectivity. With this strategy, a wide range of optically active triarylmethanes have been achieved in high yields with good to excellent enantioselectivities.

The on water reaction of sodium telluride with electrophiles has been explored. Na₂Te, generated in situ through the rongalite (sodium hydroxymethanesulfinate)‐promoted reduction of elemental tellurium, reacts with a wide variety of electrophiles, including strained heterocycles, haloalkanes, Michael acceptors, and aryl diazonium salts, providing simple and rapid access to a broad range of novel functionalised symmetrical tellurides. The methodology well tolerated the presence of versatile functional groups such as alchohols, amines, esters, nitriles, and sulfones and allowed the incorporation of tellurium atoms into biologically relevant natural‐derived products. Furthermore, in the case of the nucleophilic ring opening of epoxides, a judicious tuning of the reaction conditions enabled the synthesis of unreported β‐hydroxy‐ and β‐amino‐ditellurides, which were further employed as precursors of new functionalised unsymmetrical dialkyl tellurides. The thiol‐peroxidase catalytic activity of hydroxy‐ditellurides has also been investigated in order to compare their antioxidant properties with those of homologous tellurides.

In this work, we describe the use of Boron Dipyrromethene (BODIPY) as electron‐withdrawing group for activation of double bonds in asymmetric copper‐catalyzed [3+2] cycloaddition reactions with azomethine ylides. The reactions take place under smooth conditions and with high enantiomeric excess for a large number of different substituents, pointing out the high activation of the alkene by using a boron dipyrromethene as electron‐withdrawing group. Experimental, theoretical studies and comparison with other common electron‐withdrawing groups in asymmetric copper‐catalyzed [3+2] cycloadditions show the reasons of the different reactivity of the boron dipyrromethene derivatives, which can be exploited as a useful activating group in asymmetric catalysis. Additional experiments show that the so obtained pyrrolidines can be employed as biocompatible biosensors, which can be located in the endosomal compartments and do not present toxicity in three cell lines.

ABSTRACT: NiOOH catalyst as obtained dynamically from electrodeposition of Ni2+(aq) in the borate-containing electrolyte was observed to exhibit much higher oxygen evolution activity at near-neutral pH range (7~9) compared to other NiOx based materials. Here we demonstrate that this intriguing high activity is owing to the high concentration of Ni cationic vacancy on the nascent ultra-small NiOOH particles (< 3 nm). By us-ing first-principles calculations, we compute the thermodynamics of Ni dissolution and clarify the mechanism of oxygen evolution reaction (OER) on the -NiOOH surface. We show that (i) ~4% Ni cations on the surface of -NiOOH dissolve at pH=7 and 1.73 V vs. reversible hydrogen electrode; (ii) On the pristine -NiOOH surface, OER proceeds via the “lattice peroxide” mechanism (*H2O→*OH→*O-OlattH*→O-Olatt→O2) with an overpoten-tial of 0.70 V; (iii) With the presence of Ni cationic vacancies, OER proceeds via the “hydroperoxide” mecha-nism (*OH+*H2O→*2OH→*OOH→O2) with an overpotential of 0.40 V. Our electronic structure and geomet-rical structure analyses demonstrate that the structural flexibility at the four-coordinated Ni site nearby Ni vacancy, featuring the ability to bind two terminal oxo species, is the key to boost the activity. Considering the presence of active OOH intermediate, our theory thus implies that the ultra-small oxide nanoclusters with ample cation vacancies could be a paradigm in catalyst design for oxidation reactions.

Selective hydrogenation of cinnamaldehyde (CAL) is an important reaction since the main products, cinnamic alcohol (COL) and hydrocinnamaldehyde (HCAL), are used in various fields, such as production of pharmaceutical intermediates, chemicals, perfume, and fragrances. In recent years, numerous metal-based catalysts and significant study achievements have been reported. Thus, this review focuses on selective hydrogenation of CAL to target products in terms of metal-based catalysts, and summarizes recent developments in this reaction with different catalysts, including Pt-, Pd-, Ru-, Ni-, Co-, and Cu-based catalysts. In addition, the reaction mechanisms of different catalysts, the effects of catalyst substrates, the different catalyst structures, and the synergistic effects in bimetallic catalysts are discussed. And lastly, the limitations and barriers encountered for noble metal and non-noble metal catalysts in the current study are discussed as well as potential research trends.