Te2− modulated heterogeneous remodeling of S atoms in ultrathin ZnIn2S4 nanosheets containing S vacancies synergistically enhances CO2 photoreduction

Abstract

Reconfiguration of in situ heterojunction composites without interfacial resistance by substitution of homologous anions for the formation of gradient work function differences inducing the formation of built-in electric field is an effective strategy to enhance the charge separation efficiency. Herein, Te2−/ZnIn2S4-VS (Te2−/ZIS-VS) in situ heterojunction was synthesized by substitution of Te2− ions for S2− in ultrathin ZIS containing S vacancies, which can significantly promote photogenerated charge separation, surface electron enrichment, and CO2 adsorption/activation. The presence of S vacancies and adjacent Te2−/S2− double anions, the double active sites constructed by defect engineering promote the desorption of *CO molecules while inhibiting the protonation toward *CHO, which was more favorable for selective CO2 photoreduction to CO. The experimental results showed that the CO yield of Te2−/ZIS-VS was significantly increased to 672.1 μmol g−1 h−1 compared with pristine ZIS (54.3 μmol g−1 h−1) and the CO selectivity was close to 83 %. Notably, the life cycle assessment (LCA) of Te2−/Znln2S4 nanosheets with S-vacancy was performed. The evaluation results showed that most of the 17 impact categories showed low overall impact values and were environmentally friendly. Based on the results of this LCA, suggestions were put forward to further optimize the product to reduce carbon emissions.