Activating Basal Surface of Palladium by Electronic Modulation via Atomically Dispersed Nitrogen Doping for High-Efficiency Hydrogen Evolution Reaction

Surface doping by atomically dispersed heteroatoms has become one of the most promising strategies for facilitating the catalytic activity of non-noble transition metals to replace platinum-based catalysts in the hydrogen evolution reaction (HER). However, the underlying mechanism for the atomically dispersed heteroatoms to modulate the electronic structure and the HER activity of a metal surface is still ambiguous. Moreover, the active catalytic region is limited by the small fraction of doped atoms, and the remaining basal surface is inactivated. Here, we demonstrate that the nitrogen doping is atomically dispersed on the palladium surface, which can achieve the near-thermoneutral hydrogen adsorption and promote the HER activity of the basal surface. The theoretical modeling reveals that the dispersed nitrogen atoms attract electrons from palladium and downdrift the d-band center for accelerating the hydrogen desorption. Our work offers understandings of atomically dispersed nitrogen doping on the surface of transition metals and paves the way for a further optimization of nonprecious-metal HER electrocatalysts.