Design of a Silicon Photocatalyst for High-Efficiency Photocatalytic Water Splitting

Abstract

Metallurgical silicon was studied for photocatalytic H2 evolution activity. It has been found that metallurgical silicon with large particle size (above 800 nm) possesses poor photocatalytic activity because of the deteriorating photoelectric performance of the low-purity silicon. After size reduction (around 400 nm) and metal nanoparticle decoration, the photocatalytic performance was significantly enhanced to 1003.3 μmol·g–1·h–1. However, the photocatalytic performance of the Cu-, Ag-, and Pt-decorated silicon is degraded with the increase of time. Moreover, the degradation is independent of the metal. Electrochemical test and X-ray photoelectron spectroscopy suggested that the Mott–Schottky effect in the metal–silicon contact should be responsible for the degradation. After forming a heterojunction by vulcanizing the Ag-decorated silicon, the degradation was suppressed. Upgradation of the metal–silicon contact to form a heterojunction was a promising way to suppress the degradation and retain the high photocatalytic performance.

Silicon Suboxides as Driving Force for Efficient Light‐Enhanced Hydrogen Generation on Silicon Nanowires

“…Because SiNWs have a high capacity for “light absorption”, [ 7 ] high specific surface area, and higher bandgap than bulk silicon, [ 7,8 ] they meet the requirement for water splitting (to split the water molecule, 1.23 eV energy is necessary). [ 9–11 ] Despite this, there are few reports on SiNWs as a photocatalyst for direct hydrogen generation. [ 5,12–16 ] Liu et al.…”

Silicon Nanowires Decorated with Silver Nanoparticles for Photoassisted Hydrogen Generation

“…In this research, Ru-modified SiNWs as electrocatalysts for hydrogen evolution reaction exhibited higher performance in comparison to the pure Ru particles. Lv et al reported that after size reduction of metallurgical silicon (particle size around 400 nm) and metal nanoparticle decoration the photocatalytic performance was significantly enhanced up to 1000 μmol·g –1 ·h –1 . Hence, the decoration of SiNWs with AgNPs is a possible way to enhance the light absorption in the visible spectral range and hydrogen generation rate.…”

“…Lv et al reported that after size reduction of metallurgical silicon (particle size around 400 nm) and metal nanoparticle decoration the photocatalytic performance was significantly enhanced up to 1000 μmol•g −1 •h −1 . 19 Hence, the decoration of SiNWs with AgNPs is a possible way to enhance the light absorption in the visible spectral range and hydrogen generation rate. In this paper, three simple top-down wet-chemical-modified SiNWs with different AgNPs from electroless silver deposition (ELD), 20 silver mirror reaction (MR), 21 and native Ag particles have been investigated.…”

Surface photovoltage dynamics at passivated silicon surfaces: influence of substrate doping and surface termination

“…1 Silicon has established itself as one of the major semiconducting materials thanks to its high structural quality with suitable electronic properties such as band gap (1.12 eV), mobility, capability to be n or p doped and passivated by forming an insulating SiO 2 layer. Silicon also holds high interest in photonics 2 as a photodetector and light emitter, photocatalysis, 3 and solar cell applications. 4 Silicon based solar cells with an efficiency up to 26.7% represented about 95% of the worldwide production in 2020.…”