Construction of highly efficient Z-scheme ZnxCd1-xS/Au@g-C3N4 ternary heterojunction composite for visible-light-driven photocatalytic reduction of CO2 to solar fuel

highly efficient novel znxcd1-xs/au@g-c3n4 ternary heterojunction were fabricated by simple preparation techniques. the visible-light-driven photocatalytic co2 reduction to solar fuels were achieved by coupling gold nanoparticles between two catalysts. the gold nanoparticles acted as electron mediator, which improved the rapid extraction of photoinduced electrons and thus enhanced the co2 reduction. [Display omitted] •Z-scheme ZnxCd1-xS/Au@g-C3N4 ternary heterojunction composite was synthesized for photocatalytic CO2 reduction to solar fuels.•The gold nanoparticles improved the rapid extraction of photoinduced charge carriers and thus enhanced the reduction ability of CO2.•Methanol (CH3OH) production of ZnxCd1-xS/Au@g-C3N4 was roughly 43.6 and 32.7 times higher than pure ZCS and CN samples.•The Z-scheme heterojunction composite showed improved CO2 reduction and stability. Converting CO2 into renewable solar fuel using photocatalysts is one of the most ideal solutions for environmental challenges and energy crises. Here, the solid-solid Z-scheme Zn0.5Cd0.5S/Au@g-C3N4 (ZCS/Au@CN) heterojunction showed improved photocatalytic reduction of CO2 due to the enhanced visible light consumption, fast dissolution of photogenerated electron-hole pairs, quick interfacial transfer process of electrons, and enlarged surface area. Under visible-light irradiation, methanol (CH3OH) was produced at a rate of 1.31 μmol h−1 g−1 over ZCS/Au@CN, roughly 43.6 and 32.7 folds higher than those observed over pure ZCS and CN samples. The analytical characterization results verified the role of AuNPs as an electron mediator, which improved the rapid extraction of photoinduced electrons and enhanced the reduction ability of CO2. This work not only demonstrates a facile photodeposition assisted hydrothermal method for fabrication of ZnxCd1-xS/Au@C3N4 heterojunction composite photocatalysts but also demonstrates the possibility of utilizing ternary composites for enhanced photocatalytic reduction of CO2.