Ferroelectric switching driven photocatalytic overall water splitting in the As/In2Se3 heterostructure

Abstract

Integrating two-dimensional (2D) ferroelectric materials into van der Waals (vdW) heterostructures for photocatalytic water splitting provides new opportunities to solve the energy crisis and environmental pollution. However, the effect of polarization reversal in the ferroelectric layer of ferroelectric-based heterostructures on the photocatalytic mechanism is still unclear. Herein, utilizing density functional theory alongside non-adiabatic molecular dynamics (NAMD) simulations, the photocatalytic mechanism of the As/In₂Se₃ vdW heterostructure is systematically investigated. The NAMD results revealed that the photo-generated charge carrier transfer pathway of the As/In₂Se₃ heterostructure follows the typical type-II pathway, irrespective of the polarization states of the In₂Se₃ layer. The ultrafast interlayer photo-generated hole transfer in As/In₂Se₃-P↑ and electron transfer in As/In₂Se₃-P↓ ensure efficient charge transport, thereby enhancing the utilization efficiency of carriers. Interestingly, by adjusting the polarization direction of the In₂Se₃ layer, the As/In₂Se₃-P↑ and As/In₂Se₃-P↓ can be employed for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively. In addition, introducing P doping can significantly reduce the overpotential of the HER using As/In₂Se₃-P↓. These results provide a new insight into the photo-generated charge carrier transfer pathway of 2D ferroelectric-based vdW heterostructures.