Silicon Photocatalysts for Solar-Driven Hydrogen Production

Hydrogen is an important feedstock for various chemical processes and a promising green energy source. Sustainable and affordable production of hydrogen is extremely important for extensive commercialization of fuel cells and to reduce our reliance on steam-methane reforming which has a high carbon footprint. Technoeconomic analyses have shown that solar driven water-splitting using suspended particulate photocatalyst is a simple and cost-effective way to produce hydrogen. Nanoscale Si is an attractive photocatalyst for this process given its abundance, biocompatibility, favorable conduction band edge position for water reduction, and their solar light absorption properties. High surface area Si nanoparticles can be prepared using magnesiothermic reduction reaction. In the last five years, our research group has identified that the magnesiothermic reduction reaction parameters strongly influence the physical properties of the resulting Si particles and their catalytic performance. This presentation will summarize which Si properties are important for photocatalysis and how the reaction conditions can be chosen to maximize the hydrogen evolution rates under solar illumination. Further, the influence of photocatalysis setup and its effect on hydrogen production rates will also be discussed.