Development of a bi-compound heterogeneous cocatalyst modified p-Si photocathode for boosting the photoelectrochemical water splitting performance

Abstract

In this paper, a MoS₂/Rh–P bi-compound heterogeneous cocatalyst is developed to improve the photoelectrochemical (PEC) water splitting performance of a p-Si photocathode. Compared with the single cocatalysts (MoS₂ and Rh–P), the bi-compound heterogeneous cocatalyst MoS₂/Rh–P on the p-Si photocathode surface exhibits a much better hydrogen evolution reaction (HER) activity at the electrode/electrolyte interface, which is attributed to the synergistic electronic effect between MoS₂ and Rh–P materials. Meanwhile, the TiO₂ layer could serve as a linker between p-Si and the surface cocatalyst to optimize the interface energy, further promoting the photocarrier transfer process within the system. Thus, the as-prepared p-Si–TiO₂–MoS₂/Rh–P photocathode exhibits excellent PEC performance with a high photocurrent density of −24.1 mA cm⁻² at 0 V (vs. RHE) and a positive onset potential of 0.43 V (vs. RHE). And the bi-compound heterogeneous cocatalyst provides a feasible strategy for boosting the PEC hydrogen evolution.