Chinese scientists have made breakthrough progress in research on hydrogen production via water-gas shift (WGS)

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Chinese scientists make breakthrough progress in hydrogen production via water-gas shift (WGS) reaction. Author/Source: Gasification World. Date: February 3, 2021. Clicks: 5. It was reported recently on the official website of China Science News that hydrogen, as a typical representative of clean energy, is highly regarded; however, due to its reactive chemical properties, issues related to the efficiency and safety of its production, storage, and transportation have long posed challenges for both the industrial and academic communities. New progress has been made in the joint research conducted by Professor Martin’s team from the School of Chemistry and Molecular Engineering at Peking University, together with Professor Ishikawa’s team from Dalian University of Technology and Professor Zhou Wu’s team from the University of Chinese Academy of Sciences; the relevant findings were recently published in Nature. The research team designed and synthesized an interfacial catalytic structure composed of highly dense, highly dispersed atomic-scale platinum (Pt) species and cubic molybdenum carbide (α-MoC), thereby creating a highly efficient and stable Pt/α-MoC catalyst. This catalyst can be used to catalyze the water-gas shift (WGS) reaction for hydrogen production, and it is also the WGS catalyst with the best catalytic performance reported to date. The WGS reaction is one of the important methods for producing pure hydrogen in the field of energy and chemical engineering. Restricted by chemical equilibrium, it is more advantageous to carry out the WGS reaction at low temperatures, which imposes higher demands on catalyst activity and durability. As early as 2017, Martin’s team and others published in journals such as Nature and Science that Pt/α-MoC and Au/α-MoC catalysts could achieve extremely high hydrogen production efficiencies at low temperatures, opening up new pathways for efficient hydrogen production via WGS as well as for the purification of crude hydrogen. “α-MoC exhibits excellent properties for dissociating water molecules (H2O); it can dissociate H2O and release hydrogen at room temperature. However, if the hydroxyl species adsorbed on the surface and dissociated at a certain temperature are not converted in a timely manner, deep oxidation of α-MoC can occur during the prolonged catalytic process, leading to catalyst deactivation. Therefore, how to achieve a perfect match between the adsorption and activation rates of H2O and carbon monoxide (CO) is a key scientific issue for further improving the catalytic reaction activity and long-term stability. ”Ishikawa told China Science News. In this study, the research team developed an interfacial catalytic system composed of highly dense and well-dispersed atomic-scale Pt species and α-MoC, allowing for the direct observation of the dissociation pathway of H2O on the α-MoC surface. Meanwhile, the presence of highly dense atomic-scale Pt species effectively promoted the adsorption and activation of CO; this not only accelerated the reaction leading to the generation of reactive oxygen species from H2O dissociation but also opened up a new path for low-temperature hydrogen production based on the direct dissociation of CO. “Compared with other WGS catalysts, the Pt/α-MoC catalyst exhibits higher activity and a wider range of operating temperatures, enabling hydrogen production at low temperatures; furthermore, researchers have also found methods to stabilize the Pt/α-MoC catalyst. ”Martin said. It is understood that the Pt/α-MoC catalyst exceeds the catalytic activity limits estimated in the U.S. Department of Energy’s fuel cell development plan for vehicles in 2004, offering good prospects for application. The American Chemical Society reported on the use of catalysts to advance fuel cell vehicles, describing it as an important discovery. Currently, the technology for preparing Pt/α-MoC catalysts has been patented. Martin said that by studying the mechanism of the Pt/α-MoC catalyst, the research team also uncovered the reasons for its high efficiency, providing new insights for the development of more efficient catalysts in the future.