Joule
ArticleDomino catalysis for selective dehydrogenation of ethane with shifted thermodynamic equilibrium
Context & scale
Ethylene is one of the most important platform molecules in the modern chemical industry and building units of polymers. Generally, ethylene is produced from naphtha cracking, which relies on petroleum feedstock. The catalytic dehydrogenation of ethane (EDH) has been regarded as a promising non-petroleum route to produce ethylene, because ethane has been abundantly produced from shale gas. However, the non-oxidative EDH is thermodynamically limited, resulting in insufficient ethane conversions. In this work, we overcome this limitation through a domino process by interleaving MnOx@Na2WO4 oxide with the dehydrogenation catalyst (Co-zeolite) in multiple-bed manners. The ethane dehydrogenation and selective hydrogen consumption occurred alternately in this process, thus shifting the reaction equilibrium to give significantly improved ethane conversions where the high ethylene selectivity was maintained.
Graphical abstract
Introduction
Cascade reactions over multiple functional catalysts have been extensively explored for optimizing the conversions and selectivities in various processes.1,2,3,4,5,6,7,8 A typical one is the non-oxidative dehydrogenation of light alkanes, which are limited thermodynamically7,8,9,10,11,12,13,14,15,16,17 and usually require high temperatures to realize the commercially desired one-pass yields. A more recent trend is removing the hydrogen product to shift the equilibrium via dehydrogenation and hydrogen combustion cascades over the rationally designed bifunctional catalysts in continuous reactions or chemical-looping modes.18,19,20,21,22,23,24,25,26,27 However, this methodology presents a great challenge in controlling the selective hydrogen combustion,7,22,28,29 which is that the alkanes and olefins are also combusted to undesired CO/CO2 products that result in insufficient selectivity to olefins. To overcome this issue, general strategies were focused on engineering the catalyst surface by chemical modification to poison the active sites of overoxidation.20,21,22 In some cases, the dehydrogenation activity was also reduced. As a result, the dehydrogenation requires a high reaction temperature for achieving desired per-pass conversion, such as 700°C–850°C for the ethane dehydrogenation (EDH).20,30,31
On the other hand, many biological systems provide solutions for this problem, where the intermediate molecules are repeatedly transferred and reacted between spatially separated active sites with different functions for consuming the specific products and/or intermediates, which benefits the high yield of target products.32 This motivated our exploration of reactions with spatially separated active sites for dehydrogenation and hydrogen combustion, respectively. Key to the successes is to employ sodium tungstate-modulated manganese oxide (MnOx@Na2WO4, mixed phases of Mn2O3/MnO2 and Na2WO4, Figures S1 and S2) as a promoter for selective hydrogen combustion but inactive for the oxidation of hydrocarbons. By physically interleaving a known dehydrogenation catalyst of cobaltosilicate zeolite (CoS-1, cobalt loading at 1.86 wt %, Figures S3–S5)33,34 and this MnOx@Na2WO4 promoter in a domino mode, the EDH and hydrogen combustion occur alternately on the spatially separated sites at the industrially desired temperature (e.g., 590°C), simultaneously achieving high ethane conversion by shifting the thermodynamic equilibrium and ethylene selectivity by hindering the overoxidation.
Section snippets
Domino catalysis in EDH
Data characterizing the performances in the EDH (partial pressure at 0.8 bar, helium as balance) are shown in Figure 1. Under the given reaction conditions, the ethane conversion at thermodynamic equilibrium was 15.5% (Figures 1A and S6). The sole CoS-1 catalyst efficiently catalyzed the reaction, exhibiting the ethane conversion at 15.4%, which is close to the thermodynamic equilibrium with a 98.7% selectivity to ethylene and a stoichiometric hydrogen product. When a MnOx@Na2WO4 bed was packed
Selectivity in hydrogen and hydrocarbon combustion
The MnOx@Na2WO4 is crucial in domino catalysis because of its superior selectivity for combusting hydrogen rather than ethylene. This similar trend was previously observed on Na2WO4-modified multiple oxides, which have worked in a wide range of temperatures for hydrogen combustion.20,21,23,39,40 However, how to combine such features in the EDH process to realize high ethane conversions at mild temperatures was still a great challenge, but here, it was achieved on the domino catalysts. The
Lead contact
Further information and requests for resources should be directed to and will be fulfilled by the lead contact.
Materials availability
This study did not generate new unique reagents.
Acknowledgments
This work was supported by the National Key Research and Development Program of China (2022YFA1503502) and the National Natural Science Foundation of China (22288101, 22241801, and U21B20101). We thank Fang Chen at Zhejiang University for kindly helping in SEM and TEM characterization and Dr. Xuefeng Chu at Jilin Jianzhu University for help in XPS characterization.
Author contributions
X.Q. carried out the catalyst preparation, characterization, and catalytic tests. H.W. and B.Y. performed the theoretical
References (45)
- et al.
Highly selective conversion of carbon dioxide to aromatics over tandem catalysts
Joule
(2019) - et al.
Can CO2-assisted alkane dehydrogenation lead to negative CO2 emissions?
Joule
(2022) - et al.
Manganese silicate based redox catalysts for greener ethylene production via chemical looping–oxidative dehydrogenation of ethane
Appl. Catal. B
(2018) - et al.
Selective hydrogen combustion as an effective approach for intensified chemical production via the chemical looping strategy
Fuel Process. Technol.
(2021) - et al.
Non-oxidative conversion of ethane to ethylene over transition metals supported on Mg–Al mixed oxide: preliminary screening of catalytic activity and coking ability
Catal. Commun.
(2007) - et al.
Lanthanum manganite-based perovskite as a catalyst for co-production of ethylene and hydrogen by ethane dehydrogenation
J. Catal.
(2019) - et al.
Enhanced ethylene selectivity and stability of Mo/ZSM5 upon modification with phosphorus in ethane dehydrogenation
J. Catal.
(2018) - et al.
Ethane dehydrogenation on Pt/Mg(Al)O and PtSn/Mg(Al)O catalysts
J. Catal.
(2010) - et al.
Effect of sodium tungstate promoter on the reduction kinetics of CaMn0.9Fe0.1O3 for chemical looping–oxidative dehydrogenation of ethane
Chem. Eng. J.
(2020) - et al.
Core-shell Na2WO4/CuMn2O4 oxygen carrier with high oxygen capacity for chemical looping oxidative dehydrogenation of ethane
Fuel
(2021)
Alumina-supported manganese oxide catalysts: I
J. Catal.
Propane to olefins tandem catalysis: a selective route towards light olefins production
Chem. Soc. Rev.
Catalytic alkane metathesis by tandem alkane dehydrogenation-olefin metathesis
Science
Polyethylene upcycling to long-chain alkylaromatics by tandem hydrogenolysis/aromatization
Science
Recent advances in direct synthesis of value-added aromatic chemicals from syngas by cascade reactions over bifunctional catalysts
Adv. Mater.
Ternary platinum–cobalt–indium nanoalloy on ceria as a highly efficient catalyst for the oxidative dehydrogenation of propane using CO2
Nat. Catal.
Tandem In2O3-Pt/Al2O3 catalyst for coupling of propane dehydrogenation to selective H2 combustion
Science
Near 100% ethene selectivity achieved by tailoring dual active sites to isolate dehydrogenation and oxidation
Nat. Commun.
Subsurface catalysis-mediated selectivity of dehydrogenation reaction
Sci. Adv.
Propane dehydrogenation: catalyst development, new chemistry, and emerging technologies
Chem. Soc. Rev.
In situ formation of ZnOx species for efficient propane dehydrogenation
Nature
First-principles design of a single-atom–alloy propane dehydrogenation catalyst
Science
Cited by (3)
Alkane dehydrogenation in scalable and electrifiable carbon membrane reactor
2023, Cell Reports Physical ScienceTuning Pt Location and Intimacy between Pt-Acid Active Sites in Pt/ZSM-5 Bifunctional Catalysts for Effective Alkylation of Benzene with Ethane
2024, Industrial and Engineering Chemistry ResearchZeolite catalysts for non-oxidative ethane dehydrogenation to ethylene
2024, EES Catalysis