Theoretical Evaluation of Electrochemical Nitrate Reduction Reaction on Graphdiyne-Supported Transition Metal Single-Atom Catalysts.

The electrochemical reaction can be applied as a powerful method to eliminate the pollution of nitrate (NO ) and as a feasible synthesis to enable the conversion of nitrate into ammonia (NH) at room temperature. Herein, density functional theory calculations are applied to comprehensively analyze the electrochemical nitrate reduction reaction (NORR) on graphdiyne-supported transition metal single-atom catalysts (TM@GDY SACs) for the first time. It can be found that the vanadium-anchored graphdiyne (V@GDY) displays the lowest limiting potential of -0.63 V versus a reversible hydrogen electrode among the investigated systems in this work. Notably, the competing hydrogen evolution reaction is relatively restrained due to the comparatively weak adsorption of the H proton on the TM@GDY SACs. Moreover, higher energy intake is needed to overcome the energy barrier during the formation of byproducts (NO, NO, NO, and N) on V@GDY without applying extra electrode potential, showing the selectivity of NH in the NORR process. The ab initio molecular dynamics simulation denotes that the V@GDY possesses excellent structure stability at the temperature of 600 K without much distortion, compared with the initial shape, indicating the promise for synthesis. This study not only offers a feasible NORR electrocatalyst but also paves the way for the development of the NORR process.