2D ultrathin ZnIn2S4 nanosheets anchored on octahedral TiO2/Ti3C2 Z-scheme heterostructure for enhanced photocatalytic CO2 reduction

The low carbon dioxide (CO2) conversion efficiency of semiconductor heterojunction-based photocatalysts is a lingering issue in the field of solar energy-driven catalysis. In this study, sandwich-like hierarchical heterostructures of two-dimensional (2D) ultrathin ZnIn2S4 nanosheets and octahedral titanium dioxide (TiO2) nanoparticles were grown in situ on Ti3C2 MXene via a hydrothermal method. Significantly, the ZnIn2S4@TiO2/Ti3C2 ternary heterostructure shows better CO2 reduction activity and the optimal catalyst has carbon monoxide (CO) and methane (CH4) production rates of 59.8 and 23.44 μmol g−1, respectively, within 8 h of simulated solar light illumination, which was greater than that pristine ZnIn2S4. These ultrathin ZnIn2S4 nanosheets and TiO2/Ti3C2 Schottky-junctions assisted the heterostructures to reduce photogenerated electron–hole recombination and increase photogenerated charge-transfer and separation in a Z-scheme pathway. ZnIn2S4@TiO2/Ti3C2 heterostructure photocatalysts have superior photocatalytic CO2 conversion and good stability compared to pure ZnIn2S4. Thus, the suggested approach is to design a highly-efficient photocatalyst for environmental remediation.