Fabrication of Ultrafine Cu₂O Nanoparticles on W₁₈O₄₉ Ultra-Thin Nanowires by In-Situ Reduction for Highly Efficient Photocatalytic Nitrogen Fixation

Photocatalytic ammonia synthesis technology is one of the important methods to achieve green ammonia synthesis. Herein, two samples of Cu ion-doped W18O49 with different morphologies, ultra-thin nanowires (Cu-W18O49-x UTNW) and sea urchin-like microspheres (Cu-W18O49-x SUMS), are synthesized by a simple solvothermal method. Subsequently, Cu2O-W18O49-x UTNW/SUMS is synthesized by in situ reduction, where the NH3 production rate of Cu2O-W18O49-30 UTNW is 252.4 mu mol g(-1) h(-1) without sacrificial reagents, which is 11.8 times higher than that of the pristine W18O49 UTNW. The Cu2O-W18O49-30 UTNW sample is rich in oxygen vacancies, which promotes the chemisorption and activation of N-2 molecules and makes the N equivalent to N bond easier to dissociate by proton coupling. In addition, the in situ reduction-generated Cu2O nanoparticles exhibit ideal S-scheme heterojunctions with W18O49 UTNW, which enhances the internal electric field strength and improves the separation and transfer efficiency of the photogenerated carriers. Therefore, this study provides a new idea for the design of efficient nitrogen fixation photocatalysis.