Electron modulation by atomic Ir site decoration in porous Co/N co-doped carbon for electrocatalytic hydrogen evolution

The rational design of materials at atomic scale as efficient and stable electrocatalysts for hydrogen evolution reaction(HER)is critical for energy conversion.Herein,we report a novel hybrid nanostructure with iridium(Ir)and cobalt(Co)atomic pair configuration anchored in porous nitrogen-doped carbon(pNC)nanosheets(denoted as IrCo-pNC)for electrocatalytic HER.Experimental investigations and theoretical calculations reveal that the interaction between Ir and Co species in pNC promotes electron accumulation and depletion around isolated Ir and Co atoms,respectively,resulting in a local asymmetry electron density distribution.Density functional theory calculations also suggest that the electrons transfer from Co to adjacent Ir atom causing the down shift of the d-band center of Ir 5d in IrCo-pNC catalyst,thus optimizing the adsorption of hydrogen on Ir sites.The as-prepared IrCo-pNC exhibits significant HER performance with an overpotential of 21 mV to achieve a current density of 10 mA·cm^(−2)in 0.5 M H2SO4.This work provides insight into the role of asymmetry electron density distribution in nanomaterials in regulating HER electrocatalysis.