Electronic modulation optimizes intermediate adsorption on Ni sites via coupling NiCo alloy in N-doped carbon dodecahedrons toward efficient hydrogen evolution reaction

Abstract

Developing efficient, stable, and low-cost metal electrocatalysts for hydrogen evolution reaction (HER) is significant for clean energy conversion technology. Regulating the adsorption energy of H intermediates by modulating the electronic structure of the active sites of the electrocatalyst for approximating the equilibrium potential is of primality importance to overcoming the kinetic sluggishness of the HER, yet still represents a great challenge. Herein, we have reported a NiCo alloy electrocatalyst supported by an N-doped carbon dodecahedral substrate with a strong electron coupling between the NiCo alloy and NC to improve the obstacles of both activity and stability for HER. Benefiting from the above electron coupling effect, the Ni₁Co₂/NC catalyst exhibits enhanced HER activity and stability in an acid electrolyte. Specifically, the Ni₁Co₂/NC exhibits enhanced acid HER activity with a low overpotential of 114.7 mV at 10 mA cm⁻² and robust stability with negligible activity decay after 5000 cycles, which are superior to its counterpart. Theoretical calculations revealed that the electron coupling between the NiCo alloy and NC could effectively moderate the electronic states of NiCo alloy, dramatically decreasing the free energy for H adsorption and leading to optimal adsorption/desorption of *H, thereby promoting the overall HER kinetics. This study provides a new perspective on constructing catalysts of HER with low-cost, well-designed structures and superior performance for clean energy conversion technology.