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

• We reported CeO x -S/ZnIn2S4 catalysts with size of CeO x -S clusters less than 2 nm. • The CeO x -S/ZnIn2S4 hybrid catalysts hold rich surface defects. • CeO x -S/ZnIn 2 S 4 had higher activity in photocatalytic CO 2 reduction than ZnIn 2 S 4. • Oxygen vacancies on CeO x -S/ZnIn 2 S 4 can trap electrons and then transfer to CO 2. • The Ce–S can lower activation energy barrier during CO 2 reduction. Engineering the electronic properties of heterogeneous catalysts is an important strategy to enhance their activity towards CO 2 reduction. Herein, we prepared partially sulfurized cerium oxide (CeO x -S) nanoclusters with the size less than 2 nm on the surface of ZnIn 2 S 4 layers. Surface electronic properties of CeO x -S nanoclusters are facilely modulated by cerium coordination to sulfur, inducing the emergence of abundant Ce3+ and oxygen vacancies. For the photoreduction of CO 2 , CeO x -S/ZnIn 2 S 4 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 ZnIn 2 S 4 catalyst using triethylamine as a sacrificial electron donor. Further mechanistic studies reveal that the photogenerated electrons are trapped by oxygen vacancies on CeO x -S/ZnIn 2 S 4 catalysts and subsequently transfer to CO 2 , benefiting the activation of CO 2. Moreover, the extremely high selectivity of CO is derived from the weak adsorption of CO on the surface of CeO x -S/ZnIn 2 S 4 catalysts. [ABSTRACT FROM AUTHOR]