An efficient screening strategy towards multifunctional catalysts for the simultaneous electroreduction of NO3-, NO2- and NO to NH3

Multifunctional electrocatalysts that simultaneously reduce all NOx species (NO3-, NO2- and NO) to NH3 can deliver superior efficiency compared with that for individual species. Herein, by using the first-principles method, an efficient strategy was proposed to screen NOxRR multifunctional electrocatalysts, which focuses on the key protonation process of the essential NORR for the NOxRR. Taking double-atom catalysts (DACs) with transition-metal dimer (M1/M2 = V, Cr, Mn, Fe, Co, Ni, and Cu) embedded N-doped graphene as examples, we showed that the proposed strategy was effective for electrocatalyst screening, and we identified Cu-2@NG as the best one, with rather low limiting potentials of -0.36, -0.32, and -0.30 V for the NO3RR, NO2RR, and NORR, respectively. Furthermore, a simple descriptor for evaluating electrocatalytic activity was established. And the physical mechanism in terms of the electronic structures was analyzed for the Cu-2 DAC case in view of NO activation. Finally, from the screening test in some 4d and 5d late transition-metal based DACs, the proposed strategy was confirmed to be feasible to find another NOxRR multifunctional electrocatalyst. Our work provides a procedure for efficiently screening multifunctional electrocatalysts to simultaneously reduce all NOx species to synthesize NH3 and sheds light on the atomic mechanisms for NOx electroreduction as well.

Automated summary

This study proposes an efficient strategy to screen multifunctional electrocatalysts that can simultaneously reduce all NOx species. By using the first-principles method and taking double-atom catalysts embedded N-doped graphene as examples, the proposed strategy is proven to be effective, and Cu-2@NG is identified as the best catalyst.