Single transition‐metal atoms anchored on a novel Dirac‐dispersive π‐π conjugated holey graphitic carbon nitride substrate: computational screening toward efficient bifunctional OER/ORR electrocatalysts

Abstract Nonprecious‐metal‐group single‐metal‐atom catalysts with bifunctional catalytic capabilities toward the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are highly sought after in energy‐conversion and storage technology. However, producing renewable and sustainable energy sources remains challenging. Currently, single‐transition metal atoms anchored on π‐π conjugated two‐dimensional (2D) graphitic carbon nitride substrates form π‐d conjugated conductive channels that enhance the overall electrocatalytic activity. Herein, first‐principles calculations were carried out to design and demonstrate a novel macropore graphitic carbon nitride (g‐C 10 N 3 ) as a promising 2D electrocatalyst substrate to support single‐transition metal (TM, from Sc to Au). The “donation‐acceptance” charge interaction in the TM‐N 2 moiety effectively balances the adsorption strength of oxygenated intermediates in Ni@g‐C 10 N 3 and Rh@g‐C 10 N 3 , making them effective bifunctional OER/ORR electrocatalysts with IrO 2 /Pt‐beyond overpotentials being as low as 0.39/0.38 V and 0.54/0.44 V, respectively. Additionally, they possess high stability and conductivity and are less susceptible to oxidation and corrosion under working conditions. This guarantees high activity under ambient conditions. Then, the origin of the OER/ORR activity of TM@g‐C 10 N 3 is explained using multilevel descriptors: intrinsic φ , Bader charge, integral crystal orbital Hamilton population (ICOHP), bond length, and d‐band center ( ε d ). In particular, for optimal Ni@g‐C 10 N 3 , the clear hybridization between the Ni‐d orbital and surface O‐p orbital causes the paired electrons to occupy the bonding orbitals. This enables OH* to be adsorbed on the Ni@g‐C 10 N 3 , thereby achieving the highest catalytic performance.