Periodic Macroporous CuCe Catalyst with Prereduced Active Sites for Preferential CO Oxidation
Feiyang Hu, Yifei Wang, Fen Liu, Krongthong Kamonsuangkasem, Xiaohan Chen, Qian Liu, Ling Wei, Xia Gong, Longmei Li, Sibudjing Kawi, Lei GongAbstract
The regulation of Cu valence states, which stabilizes the strongly adsorbed active sites, is a critical factor in improving the CO-PROX reaction performance. Herein, spherical CuCe catalysts were synthesized via the colloidal template method, with the Cu valence states subsequently regulated by prereduction. Among the prepared catalysts, the sample reduced at 100 °C (CuCe-100) exhibited superior activity, achieving 100% CO conversion at 120 °C and maintaining complete conversion up to 180 °C. As revealed by XRD, XPS, XANES, and EXAFS, the superior activity of CuCe-100 is attributed to its higher Cu+, which facilitates oxygen vacancy cycling and thereby enhances CO adsorption. Furthermore, key intermediate species (COOH–, Cu+–CO) were identified by in situ DRIFTS, and DFT verified that CO adsorption is most favorable on the Cu2O (111) surface. This work clarifies at the atomic level that Cu+ is the key adsorption site for CO, thereby deepening the understanding of CO-PROX and paving the way for designing high-performance catalysts via valence regulation.