Tuning Double Layer Structure of WO3 Nanobelt for Promoting the Electrochemical Nitrogen Reduction Reaction in Water

Electrochemical fixation of nitrogen to ammonia with highly active, highly selective and low cost electrocatalysts is a sustainable alternative to the extremely energy- and capital-intensive Haber-Bosch process. Herein, we demonstrate a near electroneutral WO3 nanobelt catalyst to be a promising electrocatalyst for selective and efficient nitrogen reduction. The concept of near electroneutral interface is demonstrated by fabricating WO3 nanobelts with small zeta potential value on carbon fiber paper, which ensures a loose double layer structure of the electrode/electrolyte interface and allows nitrogen molecules access the active sites more easily and regulates proton transfer to increase the catalytic selectivity. The WO3/CFP electrode with optimal surface charge achieves a NH3 yield rate of 4.3 mu g.h(-1).mg(-1) and a faradaic efficiency of 37.3% at -0.3 V vs. RHE, rivalling the performance of the state-of-the-art nitrogen reduction reaction electrocatalysts. The result reveals that an unobstructed gas-diffusion pathway for continually supplying enough nitrogen to the active catalytic sites is of great importance to the overall catalytic performance.