Redispersion of exsolved Cu nanoparticles on LaFeO3 photocatalyst for tunable photocatalytic CO2 reduction.

• A Cu based perovskite photocatalyst toward CO 2 conversion was fabricated by consecutive in-situ exsolution/redispersion strategy. • The uniformly dispersed Cu site and modified band structure is beneficial for enhancing light absorption and photocatalytic activity. Excessive exploitation and depletion of fossil fuels have led to the escalation of CO 2 emissions, which are responsible for global climate deterioration. Cu-based solid catalysts can transform CO 2 into various hydrocarbons via a sustainable photocatalytic pathway. Herein, we fabricated a Cu-decorated LaFeO 3 photocatalyst using a sequential in situ exsolution (in H 2)/redispersion (in N 2) strategy. The dispersion of Cu was significantly enhanced (∼3 times), i.e., from 13.8 % (exsolved) to 41.4 % (redispersed). The combined theoretical and experimental results confirmed the successful formation of uniformly dispersed Cu active sites for efficient CO 2 adsorption and photocatalytic conversion. The enhancement of light absorption and manipulation of the band structure were also collectively achieved, offering an optimized catalyst involving superior CO and CH 4 production compared to its counterparts. In addition, photocatalytic water splitting was significantly suppressed, suggesting high selectivity of the photocatalytic pathway. This study offers a new perspective on the design principle of photocatalysts for selective CO 2 conversion. [ABSTRACT FROM AUTHOR]