Integrating biomass and minerals into photocatalysts for efficient photocatalytic N2 fixation coupled with biomass conversion

Photocatalytic nitrogen fixation is considered a promising strategy for addressing the energy crisis; however, it suffers from sluggish thermodynamics and kinetics. The photoredox coupling reaction has the potential to overcome the above obstacles by co-producing ammonia fuel and valuable chemicals. In this study, we propose a solar-driven catalysis system based on natural minerals and biomass waste for coupling photocatalytic N2 reduction with biomass oxidation, thereby realizing the concept of “trash to treasure”. Specifically, Fe-modified attapulgite (Fe-ATP)-supported hydrothermal carbon (HTCC) nanosheets were synthesized by a microwave hydrothermal method to form an HTCC/Fe-ATP heterostructure mimicking a natural branch-leaf morphology. HTCC/Fe-ATP exhibited significantly improved carrier separation and transport efficiency due to the formation of its S-scheme heterostructure. Consequently, the 30% HTCC/Fe-ATP composite demonstrated remarkable photocatalytic N2 fixation capability coupled with the conversion of benzyl alcohol under visible light. Notably, the ammonia production rate reached 102.8 μmol g−1 h−1, while the yield of benzaldehyde reached 155 μmol g−1 h−1, and the selectivity was close to 99%. The nanocomposite exposes abundant active sites for N2 adsorption and effectively enhances visible light absorption. Furthermore, the presence of benzyl alcohol in the reaction system effectively improves the nitrogen fixation efficiency. This study presents a novel perspective for valorizing N2 and biomass into value-added chemicals in a photo-driven catalysis system.