来源：ACS Publications
CsPbBr3 perovskite nanocrystals have been investigated as photocatalysts for CO2 reduction owing to their excellent light-harvesting and multi-exciton generation. However, under strong illumination, Pb2+ migration and reduction to metallic Pb0 cause lattice collapse and accelerated carrier recombination, severely limiting their stability and photocatalytic performance. Here, we developed a dynamic valence regulation approach using Eu2+/Eu3+ redox couple to enhance lattice stability and improve photocatalytic performance by suppressing Pb2+ migration and Pb0 exsolution, modulating phonon coupling, and prolonging hot-carrier lifetimes. Experimental analyses suggest that Eu incorporation, together with mixed Eu valence states, is associated with improved lattice stability and reduced Pb-related destabilization under photocatalytic conditions. Moreover, Eu incorporation strengthens lattice rigidity and reduces electron–phonon coupling, which collectively slows down the thermalization of hot carriers. Transient absorption spectroscopy indicates a nearly 4-fold extension in hot-carrier lifetime compared to the pristine counterpart. As a result, the Eu-modified CsPbBr3 exhibits a 6-fold enhancement in CO2-to-CO conversion activity (300 ± 5 mmol·m−2) and maintains over 80% of its activity after continuous operation for 60 h. This work proposes a synergistic redox-lattice-carrier regulation mechanism, providing insights into the rational design of metal halide perovskite photocatalysts.