General Strategy for Enhanced Ch4 Selectivity in Photocatalytic Co2 Reduction Reactions by Surface Oxophilicity Engineering

Abstract

Rational design and control of the interactions between reaction intermediates and the surface of photocatalysts is critical to obtain high product selectivity in photocatalysis. Herein, taking CdS-based photocatalytic CO2 reduction reaction (CO2RR) as a model system, we demonstrate that CH4 selectivity can be significantly enhanced through the introduction of La3+ 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 CH4. In contrast, when Au3+ ions with low oxophilicity were doped in CdS, reduced CH4 selectivity was observed in the CO2RR. Significantly, enhanced CH4 selectivity can be achieved by doping oxophilic La3+ ions into a broad range of alternative photocatalysts including ZnO, SnS2, BiOBr, BiVO4, TaON, and CsPbBr3, which demonstrates the general strategy to enhance CH4 selectivity of photocatalytic CO2RR through increased surface oxophilicity of the photocatalysts by rare earth La3+ ion doping.

Keywords: photocatalysis, Carbon dioxide reduction, oxophilicity engineering, doping, Methane