Selective reduction of CO2 to CO under visible light by controlling coordination structures of CeOx-S/ZnIn2S4 hybrid catalysts

Engineering the electronic properties of heterogeneous catalysts is an important strategy to enhance their activity towards CO2 reduction. Herein, we prepared partially sulfurized cerium oxide (CeOx-S) nanoclusters with the size less than 2 nm on the surface of ZnIn2S4 layers. Surface electronic properties of Ce0,,-S nanoclusters are facilely modulated by cerium coordination to sulfur, inducing the emergence of abundant Ce3+ and oxygen vacancies. For the photoreduction of CO2, CeOx-S/ZnIn2S4 hybrid catalysts exhibited a CO productivity of 1.8 mmol g-1 with a rate of 0.18 mmol g(-1)h(-1), which was twice as higher as that of ZnIn2S4 catalyst using triethylamine as a sacrificial electron donor. Further mechanistic studies reveal that the photogenerated electrons are trapped by oxygen vacancies on CeOx-S/ZnIn2S4 catalysts and subsequently transfer to CO2, benefiting the activation of CO2. Moreover, the extremely high selectivity of CO is derived from the weak adsorption of CO on the surface of CeOx-S/ZnIn2S4 catalysts.