The outstanding photocatalytic degradation and hydrogen evolution of flower spherical-like MnCdS/In2S3/NiAl-LDH composites due to their heterostructure

Abstract

In this paper, a NiAl-LDH with the characteristic structure of a hydrotalc-like compound was applied as a carrier in a two-step hydrothermal process, and a MnCdS/In₂S₃/NiAl-LDH composite material was successfully prepared by loading MnCdS and In₂S₃ on the flower spherical-like surface of NiAl-LDH. The combination of NiAl-LDH with In₂S₃ and MnCdS made the band gap smaller and the light absorption range larger, thus increasing the utilization rate of light. 50% MnCdS/In₂S₃/NiAl-LDH composites had the best photoinduced charge separation and highest surface enrichment of photogenerated electrons. In the degradation experiment of crystal violet (CV), 50% MnCdS/In₂S₃/NiAl-LDH composites showed superior photocatalytic degradation efficiency (>98.5%) under full spectrum light. Furthermore, the applicability and universality of photocatalysts were studied by observing the degradation of CV by MnCdS/In₂S₃/NiAl-LDH composites under different conditions. In addition, the composites showed excellent hydrogen production capacity in the photolysis of water, in which hydrogen production within 8 hours was about 7661.51 μmol g⁻¹. By combining the results of active species capture experiments, density functional theory (DFT) calculations and photoelectrochemical experiments, the possible mechanism of double S-scheme heterojunction photocatalysis among NiAl-LDH, In₂S₃ and MnCdS was inferred, which is one of the main reasons for the enhancement of photocatalytic activity.