Enhancing the photoelectrochemical performance of p-silicon through TiO 2 coating decorated with mesoporous MoS 2

MoS 2 is a promising electrocatalyst for hydrogen evolution reaction and a good candidate for cocatalyst to enhance the photoelectrochemical (PEC) performance of Si-based photoelectrode in aqueous electrolytes. The main challenge lies in the optimization of the microstructure of MoS 2 , to improve its catalytic activity and to construct a mechanically and chemically stable cocatalyst/Si photocathode. In this paper, a highly-ordered mesoporous MoS 2 was synthesized and decorated onto a TiO 2 protected p-silicon substrate. An additional TiO 2 necking was introduced to strengthen the bonding between the MoS 2 particles and the TiO 2 layer. This meso-MoS 2 /TiO 2 /p-Si hybrid photocathode exhibited significantly enhanced PEC performance, where an onset potential of + 0.06 V (versus RHE) and a current density of – 1.8 mA/cm 2 at 0 V (versus RHE) with a Faradaic efficiency close to 100% was achieved in 0.5 mol/L H 2 SO 4 . Additionally, this meso-MoS 2 /TiO 2 /p-Si photocathode showed an excellent PEC ability and durability in alkaline media. This paper provides a promising strategy to enhance and protect the photocathode through high-performance surface cocatalysts.