Herein, Si pyramids that were prepared through chemical wet etching were used as the photocathodes for solar hydrogen production.

Technology Overview
P-doped MoS₂ was integrated on Si pyramids as photocathode for hydrogen evolution. The Efficiency was enhanced by exposing edges and activating basal planes of MoS₂. MoS_1.75P_0.25/Si pyramids showed the optimal current density of −23.8 mA cm⁻². MoS_1.75P_0.25/2 nm TiO₂/Si electrode presented the current retention of 84.0%.

Applications & Benefits
The PEC durability of photocathodes were enhanced through decoration with a TiO₂ passivation layer prepared through ALD. The current density retention of MoS_1.75P_0.25/10 nm TiO₂/Si pyramids was 84.0% after 2 h of chronoamperometric measurement.

Abstract：
Herein, molybdenum disulfide (MoS₂) integrated on Si pyramids was used as a co-catalyst to improve charge separation efficiency. Various quantities of phosphorus (P) heteroatoms were doped into MoS₂ materials to boost catalytic performance. Raman and extended X-ray absorption fine structure spectra showed that the introduction of P dopants increased the number of exposed edges and sulfur vacancies that acted as hydrogen evolution reaction (HER) active sites on MoS₂ and enhanced photoelectrochemical activity. Density functional theory calculations revealed that the HER inert basal plane of MoS₂ became catalytically active after P atoms doping. MoS_1.75P_0.25/Si pyramids presented the optimal onset potential of +0.29 V (vs. RHE) and current density −23.8 mA cm⁻². A titanium dioxide (TiO₂) layer was prepared through atomic layer deposition and served as a passivation layer that improved photocathode stability. The photocurrent retention of MoS_1.75P_0.25/10 nm TiO₂/Si pyramids was 84.0% after 2 h of chronoamperometric measurement.

Phosphorous-doped molybdenum disulfide anchored on silicon as an efficient catalyst for photoelectrochemical hydrogen generation
Author：Chen C.-J., Veeramani V., Wu Y.-H., Jena A., Yin L.-C.,Chang H.,Hu S.-F., Liu R.-S.
Year：2020
Source publication：Applied Catalysis B: Environmental  Volume 263, April 2020, 118259
Subfield Highest percentage：99%    General Environmental Science    #1/220

https://www.sciencedirect.com/science/article/pii/S0926337319310069