Rare-earth regulatory all-in-one optimization for exceptional photocatalytic CO2 methanation

To realize an ideal photocatalyst for CO 2 photoreduction to CH 4 , developing an “all-in-one” optimization system that targets every elementary step in the photocatalytic CO 2 methanation is highly desirable but remains a great challenge. Here, we present a unique rare-earth modulation strategy to collectively regulate the behaviors of light adsorption, charge separation, reactant supply, and active sites in the photocatalysis process for achieving highly active, selective, stable, and economic CO 2 methanation photocatalysts. Particularly, the proof-of-concept CuPr alloy quantum dots-decorated TiO 2 photocatalysts optimized with rare-earth elements and compositions (denoted as TiO 2 -Cu 7 Pr 1 AQDs) exhibit outstanding photocatalytic activity with a CH 4 production rate of 792.6 μmol g −1 h −1 and electron selectivity of 96.6%, surpassing various state-of-the-art photocatalysts ever reported. Comprehensive experiments and theoretical analysis demonstrate that rare-earth regulation can create multiple advantageous conditions targeting different steps, which enable TiO 2 -Cu 7 Pr 1 to fulfill the essential criteria for an ideal high-efficiency non-noble-metal photocatalyst for CO 2 methanation, including favorable light absorption, enriched reactant supply of CO 2 /H + , rapid carrier separation and transfer, as well as highly active methanation site. The proposed all-in-one design concept in this work not only develops a noble-metal-free photocatalyst with ultrahigh performance toward photocatalytic CO 2 methanation but also provides significant inspiration in various photocatalysis applications.