High Catalytic Performance of Au/Bi₂O₃ for Preferential Oxidation of CO in H₂

Preferential oxidation (PROX) of CO in hydrogen is of great significance for proton exchange membrane fuel cells (PEMFCs) that need a CO-free hydrogen stream as fuel. The key technical problem is developing catalysts that can efficiently remove CO from the H₂-rich stream within the working temperature range of PEMFCs. Herein, we design a Au/Bi₂O₃ interfacial catalyst for PROX with excellent catalytic performance, which can achieve 100% CO conversion in the PROX reaction over a wide temperature window (70-200 °C) and is perfectly compatible with the operating temperature window (80-180 °C) of PEMFCs. Moreover, the catalyst also demonstrates excellent high flow performance and long-term stability. Density functional theory (DFT) calculations reveal that the electrons transferring from Bi₂O₃ to Au and then to adsorbed perimeter CO and O₂ molecules promote the activation of CO and O₂, thus enhancing the catalytic performance of PROX.