(532de) Stabilizing Atomically Dispersed Cu for Low-Temperature Water-Gas Shift Reaction

Water-gas shift (WGS) reaction is a highly valuable industrial process for manufacturing ammonia, methanol, hydrocarbons, and hydrogen. Its most important application is in conjunction with the conversion of carbon monoxide from steam reforming of methane or other hydrocarbons in the production of hydrogen. Among the reforming catalysts, the Cu/CeO₂ catalytic systems are highly efficient for low-temperature WGS reaction due to the strong copper-ceria interaction.¹ It has been reported that atomically dispersed Cu species on rod-shaped CeO₂ nanocrystals may be more active than copper clusters/particles, and that surface oxygen vacancies on CeO₂ serve as the anchoring sites for the Cu species.² Our previous research work has demonstrated that atomically dispersed Ce species strongly anchor onto high-surface-area γ-Al₂O₃ and that these Ce species resist to calcination and reductive treatment, even at high temperatures. In this work, we used electrostatic-adsorption-assisted deposition method to first uniformly deposit atomically dispersed Ce species onto γ-Al₂O₃. Then atomically dispersed Cu species were uniformly dispersed onto the calcined Ce/γ-Al₂O₃. Atomic resolution HAADF-STEM images of the as-prepared Cu/Ce/Al₂O₃ catalyst did not show any Ce-containing or Cu-containing clusters/particles. For WGS reaction, the CO conversion over the Cu/Ce/Al₂O₃ catalyst is 56%, significantly better than the 7% over the Cu/Al₂O₃ control catalyst at (a temperature) of 300°C. Stability test at 300°C show that the as-prepared Cu/Ce/Al₂O₃ catalyst is stable for at least 8 hours. Our results demonstrate that atomically dispersed Ce species on high-surface-area Al₂O₃ can be effectively used to stabilize atomically dispersed Cu species for hydrogen production via WGS reaction.

(1) A. Chen et al, Structure of the Catalytically Active Copper–Ceria Interfacial Perimeter. Nature Catalysis 2019, 2 (4), 334–341.

(2) J. Ning, Y. Zhou, W. Shen, Atomically Dispersed Copper Species on Ceria for the Low-Temperature Water-Gas Shift Reaction. Sci. China Chem. 2020.