S-vacancy-assisted dual-sites on NiCo2S4 for photoconversion of CO2 to olefiant gas

Photocatalytc CO2 reduction, which is used to produce high-efficiency and selective olefiant (C2H4), involves significant challenges. In this study, an S-defect dual-site NiCo2S4 nanoflower assembled by using hollow tubes is synthesized. Under simulated sunlight in a gas–solid reaction system, the prepared material exhibits excellent selectivity and efficiency of photocatalytic C2H4 production. The C2H4 yields reach 80.5 μmol g−1 within 6 h and the corresponding selectivity achieves 57.1%, which are 2.5 and 2.0 times higher than those of NiCo2S4 without defects, respectively. By Carefully analyzing the structure and photoelectric property, we discover that the construction of S-defects into NiCo2S4 lattice serve as an electron trap, restricting carrier recombination and accelerating the transfer of more active electrons to CO2 molecular. The S-defects further enhance the CO2 adsorption capacity, contributing to CO2 molecular activation. This study presents a simple route for synthesizing high-performance photocatalysts for high-value C2H4 production.