Simultaneously Enhancing Catalytic Performance and Increasing Density of Bifunctional CuN₃ Active Sites in Dopant-Free 2D C₃N₃Cu for Oxygen Reduction/Evolution Reactions

Abstract

Atomically dispersed M–N–C has been considered an effective catalyst for various electrochemical reactions such as oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), which faces the challenge of increasing metal load while simultaneously maintaining catalytic performance. Herein, we put forward a strategy for boosting catalytic performances of a single Cu atom coordinated with three N atoms (CuN 3 ) for both ORR and OER by increasing the density of connected CuN 3 moieties. Our calculations first show that a single CuN 3 moiety exhibiting no catalytic performance for ORR and OER can be activated by increasing the density of metal centers, which weakens the binding affinity to *OH due to the lowered d-band center of the metal atoms. These findings stimulate the further theoretical design of a two-dimensional compound of C 3 N 3 Cu with a high concentration of homogeneously distributed CuN 3 moieties serving as bifunctional active sites, which demonstrates efficient catalytic performance for both ORR and OER as reflected by the overpotentials of 0.71 and 0.43 V, respectively. This work opens a new avenue for designing effective single-atom catalysts with potential applications as energy storage and conversion devices possessing high density of metal centers independent of the doping strategy and defect engineering, which deserves experimental investigation in the future.

Surface Curvature Effect on Dual-Atom Site Oxygen Electrocatalysis

“…The effects of inter-site distance and surface curvature on electrocatalytic activity have been discovered recently. [21][22][23] On the one hand, the previously reported surface curvature effect mimics the well-known strain effect. 24 On the other hand, to the best of our knowledge, the surface curvature effect that enhances dual-atom site catalysis remains unknown.…”

High metal loaded Cu(i)N3 single-atom catalysts: superior methane conversion activity and selectivity under mild conditions

“…24,25 Other literature studies also suggested that the CuN 3 moiety promotes the formation of reactive intermediates such as Cu–oxo species. 26–28…”

“…24,25 Other literature studies also suggested that the CuN 3 moiety promotes the formation of reactive intermediates such as Cu-oxo species. [26][27][28] Under the optimized reaction conditions, the reusability of the CuNC catalyst was assessed (Fig. S12 †).…”

Surface Curvature Effect on Dual-Atom Site Oxygen Electrocatalysis

“…The general effects of intersite distance and surface curvature on electrocatalytic activity have been discovered just recently. − On the one hand, the previously reported surface curvature effect mimics the well-known strain effect . On the other hand, to the best of our knowledge, the surface curvature effect that enhances dual-atom site catalysis and goes beyond the scaling relations remains unknown.…”