Theoretical Exploration of Electrochemical Nitrate Reduction Reaction Activities on Transition-Metal-Doped h-BP

Electrocatalytic conversion of nitrate (NO₃⁻) into ammonia can not only eliminate harmful pollutant but also provide a green method for a low-temperature ammonia synthesis. The electrochemical NO₃⁻ reduction reactions (NO₃RRs) of a series of transition-metal-doped hexagonal boron phosphide (h-BP) monolayers were comprehensively evaluated using density functional theory. The V-doped h-BP monolayer was found to stand near the top of the volcano plot with the limiting potential of -0.22 V versus a reversible hydrogen electrode, exhibiting the lowest overpotential among the investigated systems in this work. Besides, the competing hydrogen evolution reaction is significantly suppressed due to the weak adsorption of the H atom. Importantly, the structure of the V-doped h-BP monolayer can be retained very well until 900 K, illustrating the initial indication of high thermal stability and great promise for synthesis. This study not only offers an eligible NO₃RR electrocatalyst but also provides an atomic understanding of the behind mechanisms of the NO₃RR process.