Highly efficient UV-visible-infrared light-driven photothermocatalytic steam biomass reforming to H2 on Ni nanoparticles loaded on mesoporous silica

Abstract

Solar-driven photocatalytic H₂ production from biomass using semiconductor photocatalysts provides a sustainable route for the generation of renewable fuel alternatives to fossil fuels. To date, this route is limited by its relatively low H₂ production rate. Here, we report a route of photothermocatalytic steam cellulose reforming to generate H₂ and CO on a catalyst of nickel nanoparticles loaded on mesoporous silica merely using focused illumination of the entire solar spectrum or visible-infrared light. Extremely high production rates of H₂ and CO (1966.2 and 1257.7 mmol g_catalyst⁻¹ h⁻¹) together with a light-to-fuel efficiency of 5.5% are achieved. The route is also highly efficient for the steam reforming of a range of biomasses, such as agricultural and urban organic wastes. We reveal that the high catalytic efficiency is ascribed to the perfect integration of good thermocatalytic activity and intense absorption across the entire solar spectrum of loaded nickel nanoparticles, resulting in an efficient light-driven thermocatalytic process. The process is further significantly promoted by photoactivation in which carbon oxidation as the rate-determining step of steam cellulose reforming is substantially accelerated upon illumination. The substantially promoted carbon oxidation is related to chemisorbed oxygen on metallic Ni nanoparticles being activated upon illumination.