Mesoporous Silicon Nanoparticles for Solar-Driven Hydrogen Generation from Water

Abstract

Solar-driven hydrogen (H2) production from water (water splitting) by semiconductor photocatalysts has potential as a sustainable and cost-competitive alternative to current H2 production technologies. In recent years, mesoporous silicon (mp-Si) nanoparticles (NPs) have been recognized as promising photocatalysts for H2 generation. To explore the influence of the synthetic conditions on their catalytic activity, mp-Si NPs were prepared by magnesiothermic reduction while varying the annealing temperature and time. These conditions were found to affect both the crystallinity and amount of oxygen present in the mp-Si NPs. The effect of porosity on the catalytic activity of mp-Si was investigated using porous SiO2 precursors with varying pore size, which influenced the pore sizes in the mp-Si formed. The results in this thesis suggest that high crystallinity improves the performance of mp-Si photocatalysts, while high amounts of oxygen due to incomplete reduction or surface oxidation have a deleterious effect.