Atomic-layered Au clusters on α-MoC as catalysts for the low-temperature water-gas shift reaction

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Science  28 Jul 2017:
Vol. 357, Issue 6349, pp. 389-393
DOI: 10.1126/science.aah4321

Low-temperature CO removal

Carbon monoxide deactivates fuel cell catalysts, so it must be removed from H2 generated from hydrocarbons on site. Yao et al. developed a catalyst composed of layered gold clusters on molybdenum carbide (MoC) nanoparticles to convert CO through its reaction with water into H2 and CO2 at temperatures as low as 150°C. Water was activated on MoC to form surface hydroxyl groups, which then reacted with CO adsorbed on the gold clusters.

Science, this issue p. 389


The water-gas shift (WGS) reaction (where carbon monoxide plus water yields dihydrogen and carbon dioxide) is an essential process for hydrogen generation and carbon monoxide removal in various energy-related chemical operations. This equilibrium-limited reaction is favored at a low working temperature. Potential application in fuel cells also requires a WGS catalyst to be highly active, stable, and energy-efficient and to match the working temperature of on-site hydrogen generation and consumption units. We synthesized layered gold (Au) clusters on a molybdenum carbide (α-MoC) substrate to create an interfacial catalyst system for the ultralow-temperature WGS reaction. Water was activated over α-MoC at 303 kelvin, whereas carbon monoxide adsorbed on adjacent Au sites was apt to react with surface hydroxyl groups formed from water splitting, leading to a high WGS activity at low temperatures.

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