MoS2 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 MoS2, to improve its catalytic activity and to construct a mechanically and chemically stable cocatalyst/Si photocathode. In this paper, a highly-ordered mesoporous MoS2 was synthesized and decorated onto a TiO2 protected p-silicon substrate. An additional TiO2 necking was introduced to strengthen the bonding between the MoS2 particles and the TiO2 layer. This meso-MoS2/TiO2/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/cm2 at 0 V (versus RHE) with a Faradaic efficiency close to 100% was achieved in 0.5 mol/L H2SO4. Additionally, this meso-MoS2/TiO2/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.
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