Ni0.25Cu0.5Sn0.25 Nanometallic Glasses As Highly Efficient Catalyst for Electrochemical Nitrate Reduction to Ammonia

Abstract

Electrochemical nitrate reduction to ammonia (NRA) is a promising approach for alleviating energy crisis and water pollution. Current NRA catalysts are challenged to simultaneously improve the rate of the adsorption and desorption processes to further increase the total activity due to the Brønsted−Evans−Polanyi (BEP) relationships. Herein, a two-step Joule heating method is utilized for the preparation of Ni0.25Cu0.5Sn0.25 nanometallic glass containing synergistic catalytic sites to simultaneously enhance the adsorption and desorption processes. Kelvin probe force microscopy reveals a pronounced oscillatory behavior in the surface potential of Ni0.25Cu0.5Sn0.25 nanometallic glass, which is an important feature of the synergistic catalytic site, and an empirical formula is proposed to quantitatively characterize its oscillatory characteristic. In situ electrochemical Raman spectroscopy indicates the promotion of nickel and tin atoms for nitrate adsorption and ammonia desorption processes, respectively. DFT calculations demonstrated that Ni0.25Cu0.5Sn0.25 presents a wide range of adsorption energy distributions to favor the multisite synergistic catalysis. The present work provides new ideas for the design and understanding of highly active NRA catalysts.