Fabrication of Ultrafine Cu 2 O Nanoparticles on W 18 O 49 Ultra‐Thin Nanowires by In‐Situ Reduction for Highly Efficient Photocatalytic Nitrogen Fixation

Abstract Photocatalytic ammonia synthesis technology is one of the important methods to achieve green ammonia synthesis. Herein, two samples of Cu ion‐doped W 18 O 49 with different morphologies, ultra‐thin nanowires (Cu‐W 18 O 49 ‐x UTNW) and sea urchin‐like microspheres (Cu‐W 18 O 49 ‐x SUMS), are synthesized by a simple solvothermal method. Subsequently, Cu 2 O‐W 18 O 49 ‐x UTNW/SUMS is synthesized by in situ reduction, where the NH 3 production rate of Cu 2 O‐W 18 O 49 ‐30 UTNW is 252.4 µmol g −1 h −1 without sacrificial reagents, which is 11.8 times higher than that of the pristine W 18 O 49 UTNW. The Cu 2 O‐W 18 O 49 ‐30 UTNW sample is rich in oxygen vacancies, which promotes the chemisorption and activation of N 2 molecules and makes the N≡N bond easier to dissociate by proton coupling. In addition, the in situ reduction‐generated Cu 2 O nanoparticles exhibit ideal S‐scheme heterojunctions with W 18 O 49 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.