Photocatalytic syngas production from bio-derived glycerol and water on AuIn-decorated GaN nanowires supported by Si wafer

Abstract

Green syngas production from Earth-abundant and renewable resources is a viable means to achieve carbon neutrality. However, this critical path to realize net-zero carbon dioxide emissions has remained extremely challenging. In this work, by coupling GaN nanowires (NWs) with dual gold–indium nanoparticles (NPs) onto wafer-scale silicon, a novel and well-developed photocatalytic architecture of AuIn NPs/GaN NWs/Si has been assembled for the first time to produce syngas with bio-derived glycerol, water, and concentrated light as the only inputs. By correlative experimental and theoretical investigations, the AuIn/GaN interface is found to be synergistically favorable for dehydrogenating the edge functional group of –CH₂OH of the glycerol skeleton, followed by the cleavage of the inert C(sp³)–C(sp³) bond toward an ethylene glycol-based intermediate with a greatly reduced reaction energy barrier in glycerol solution. Owing to the exceptional optoelectronic and catalytic properties, syngas yields a benchmarking activity of 149.3 mmol g⁻¹ h⁻¹ under mild conditions without an extra energy input other than light. The H₂/CO ratio can be broadly tailored from 19.3 to 0.9, thus favoring various downstream products. Water plays a vital role in the highly efficient formation of syngas by providing active species e.g., hydroxyl radicals through photocatalysis. Owing to the widespread distribution of biomass, water, and sunlight, and the industrially available semiconductor platform, this work promises to efficiently and selectively produce next-generation distributed syngas.