Electron-Pump Driven Redox Design for Boosting the Reactivity of Ceria

Electron-pump behavior can enhance charge transfer and redox cycling in heterogeneous catalysis, but its dynamic evolution under reaction conditions is difficult to control. Herein, we incorporate Nb 5+ into the CeO 2 lattice via a two-step synthesis to act as a donor dopant that functions as an electron-pumping agent, tuning electron transfer and stabilizing the Ce 3+ /Ce 4+ redox cycle. Nb 5+ doping promotes Ce 3+ formation and accelerates reversible Ce 3+ /Ce 4+ cycling, which leads to improved activity, selectivity, and stability of CeO 2 for the ammonia selective catalytic reduction reaction. In situ spectroscopy measurements reveal that accelerated electron cycling stimulates the activation of a variety of molecules, including complexes of O 2, NO, and NH 3 . The optimized Ce 0.8 Nb 0.2 O 2 catalyst achieves >98% NO conversion and >98% N 2 selectivity from 200 to 400 °C and exhibits excellent H 2 O and SO 2 resistance. This work establishes a clear structure–activity relationship centered on electron-pump function reinforcement and offers mechanistic insight into controlling the dynamic electron-transfer evolution during the catalytic reaction.