Tuning single metal atoms anchored on graphdiyne for highly efficient and selective nitrate electroreduction to ammonia under aqueous environments: A computational study

By means of comprehensive density functional theory computations, single Os atom anchored on graphdiyne substrate was screened out as a promising electrocatalyst for the conversion of harmful nitrate to valuable ammonia with high stability, efficiency, and selectivity. • The potential of TM atoms on graphidyne as NO 3 RR catalysts was evaluated. • Os/GDY was identified as an ideal NO 3 RR catalyst. • NO 3 *adsorption can be utilized as a descriptor for the catalytic origin of NO 3 RR. Electrochemical reduction of nitrate (NO 3 − ) to ammonia (NH 3 ) has attracted considerable interest due to its great promises for eliminating harmful pollutants and simultaneously producing valuable NH 3 , in which the development of highly efficient and selective catalysts still remains huge challenges. Herein, by means of density functional theory (DFT) computations, we explored the potential of a series of single transition metal atoms anchored on graphdiyne (TM/GDY) as the electrocatalysts for nitrate reduction reaction (NO 3 RR) to NH 3 . By systematically evaluating the activity and selectivity of various TM/GDY candidates, Os/GDY was identified as an ideal NO 3 RR catalyst with a low limiting potential (−0.37 V) and great suppressing effect on the competing reactions. Moreover, the volcano plot was established based on the scaling relation of free adsorption energies of various intermediates, and the origin of the catalytic activity NO 3 RR was well rationalized by the descriptor of the adsorption strength and the polarized charge on the adsorbed NO 3 * species. Our results not only proposed an eligible electrocatalyst to boost NO 3 RR for ammonia synthesis, but also deeply understand the mechanism of NO 3 RR process.