General strategy for enhanced CH4 selectivity in photocatalytic CO2 reduction reactions by surface oxophilicity engineering

Rationally designing and controlling the interactions between reaction intermediates and the surface of photocatalysts is critical to obtain high product selectivity in photocatalysis. Herein, using CdS-based photocatalytic CO 2 reduction reaction (CO 2 RR) as a model system, we demonstrate that CH 4 selectivity can be significantly enhanced through the introduction of La 3+ ions with high oxophilicity on the surface of the photocatalysts. The high surface oxophilicity of the photocatalysts can increase CO* desorption energy and promote further hydrogenation to CH 4 . In contrast, when Au 3+ ions with low oxophilicity were doped in CdS, reduced CH 4 selectivity was observed in the CO 2 RR. Significantly, enhanced CH 4 selectivity can be achieved by doping oxophilic La 3+ ions into a broad range of alternative photocatalysts including ZnO, SnS 2 , BiOBr, BiVO 4 , TaON, and CsPbBr 3 , which demonstrates the general strategy to enhance CH 4 selectivity of photocatalytic CO 2 RR through increased surface oxophilicity of the photocatalysts by rare earth La 3+ ion doping.