S vacant CuIn5S8 confined in a few-layer MoSe2 with interlayer-expanded hollow heterostructures boost photocatalytic CO2 reduction

The conversion of CO 2 into CO, CH 4 and other hydrocarbons through solar energy can alleviate the energy shortage problem. We design a novel photocatalyst with S defects CuIn 5 S 8 @MoSe 2 hollow structure. The interlayer-expanded MoSe 2 can increase the adsorption of intermediates. The unique hollow structure can improve the light utilization efficiency and the electron–holes separation. CuIn 5 S 8 with S vacancies in bimetallic sites has high selectivity and photocatalytic reduction of CO 2 activity. Therefore, S vacant CuIn 5 S 8 confined in a few-layers MoSe 2 with interlayer-expanded hollow heterostructures exhibit super performance for photocatalytic CO 2 reduction. After 8-h light reaction, the outputs of CO and CH 4 for the 15.3 wt% CuIn 5 S 8 @MoSe 2 sample containing S vacancies (V s ) are 30.4 and 14.7 µmol·g −1 , respectively. The mechanism is also investigated in detail through in situ Fourier transform infrared spectroscopy technology. Graphic abstract