Efficient photothermal catalytic CO2 reduction over in situ construction ZnIn2S4@Ni(OH)2/NiO Z-scheme heterojunction

Photocatalytic reduction of CO2 into valuable chemicals has been considered as a sustainable and environmentally friendly technology, which can simultaneously alleviate the energy crisis and environmental problems that have puzzled people for a long time. Herein, we successfully synthesize defective ZnIn2S4@Ni(OH)2/NiO (ZIS@NOH/NiO) Z-scheme heterojunction photocatalysts through solvothermal and low-temperature calcination strategies. The loading of Ni(OH)2 nanosheets can increase the specific surface area of photocatalyst, and form Zscheme heterojunction with ZIS to improve the utilization of photogenerated electrons. It is worth noting that during the low-temperature calcination process, Ni(OH)2 is partially converted into NiO, and a large number of metal defects are formed, which reduces the bandgap of Ni(OH)2 and shows visible light response. In addition, the generated black defective NiO with full spectrum response and good photothermal effects can accelerate the migration of photogenerated carriers and reduce the catalytic reaction barrier of CO2. Consequently, the prepared ZIS@NOH/NiO exhibits a high yield (133.74 mu mol g-1) and selectivity (86.2 %) for CO2 to CH4, which almost is 3.2 and 11.1 times than those of ZnIn2S4@Ni(OH)2 and ZnIn2S4, respectively. Furthermore, in-situ Fourier transform infrared spectroscopy (FTIR) analysis reveal the effective adsorption of CO2 on the ZnIn2S4@Ni (OH)2/NiO surface and the high selectivity of CH4. This work will provide meaningful prospects for designing a carbon dioxide reduction photocatalyst with high conversion and selective.