Synergistic Effect of Fe Doping and Plasmonic Au Nanoparticles on WO Nanorods for Enhancing Photoelectrochemical Nitrogen Reduction.

Photoelectrochemical (PEC) nitrogen fixation has opened up new possibilities for the production of ammonia from water and air under mild conditions, but this process is confronted by the inherent challenges associated with theoretical and experimental works, limiting the efficiency of the nitrogen reduction reaction. Herein, we report for the first time a novel and efficient photoelectrocatalytic system, which has been prepared by assembling plasmonic Au nanoparticles with Fe-doped WO nanorods (denoted as WOF-Au). (i) The introduction of exotic Fe atoms into nonstoichiometric WO can eliminate bulk defects of the WO host, which resulted in narrowing bandgap energy and facilitating electron-hole separation and transportation. (ii) Meanwhile, Au nanoparticles combined with a semiconductor induce the localized surface plasmon resonance and generate energetic (hot) electrons, increasing electron density on WO nanorods. Consequently, this plasmonic WOF-Au system shows an NH production yield of 9.82 μg h cm at -0.65 V versus Ag/AgCl, which is ∼2.5-folds higher than that of the WOF (without Au loading), as well as very high stability, and no NH formation was found for the bare WO (WO). This high activity can be associated with the synergistic effects between the Fe dopant and plasmonic Au NPs on the host semiconductor WO. This work can bring some insights into the target-directed design of efficient plasmonic hybrid systems for N fixation and artificial photocatalysis.