Theoretical Evaluation\nof Electrochemical Nitrate\nReduction Reaction on Graphdiyne-Supported Transition Metal Single-Atom\nCatalysts

Abstract

The electrochemical reaction can be applied as a powerful\nmethod\nto eliminate the pollution of nitrate (NO₃^–) and as a feasible synthesis to enable the conversion of nitrate\ninto ammonia (NH₃) at room temperature. Herein, density\nfunctional theory calculations are applied to comprehensively analyze\nthe electrochemical nitrate reduction reaction (NO₃RR)\non graphdiyne-supported transition metal single-atom catalysts (TM@GDY\nSACs) for the first time. It can be found that the vanadium-anchored\ngraphdiyne (V@GDY) displays the lowest limiting potential of −0.63\nV versus a reversible hydrogen electrode among the investigated systems\nin this work. Notably, the competing hydrogen evolution reaction is\nrelatively restrained due to the comparatively weak adsorption of\nthe H proton on the TM@GDY SACs. Moreover, higher energy intake is\nneeded to overcome the energy barrier during the formation of byproducts\n(NO₂, NO, N₂O, and N₂) on V@GDY without\napplying extra electrode potential, showing the selectivity of NH₃ in the NO₃RR process. The ab initio molecular\ndynamics simulation denotes that the V@GDY possesses excellent structure\nstability at the temperature of 600 K without much distortion, compared\nwith the initial shape, indicating the promise for synthesis. This\nstudy not only offers a feasible NO₃RR electrocatalyst\nbut also paves the way for the development of the NO₃RR\nprocess.