Heterostructural Ni‐Ni0.2Mo0.8N Interface Engineering Boosts Alkaline Hydrogen Electrocatalysis

AbstractExploring efficient and low‐cost bifunctional catalysts for hydrogen evolution reaction (HER) and hydrogen oxidation reaction (HOR) is highly desirable for the achievement of unitized regenerative fuel cells. Herein, a facile method to prepare hetero‐interfacial Ni‐Ni0.2Mo0.8N nanosheets with tailored d‐band for efficient alkaline hydrogen electrocatalysis is presented. Mechanism studies indicate that interface engineering can downshift the d‐band center of Ni‐Ni0.2Mo0.8N nanosheets due to the electron transfer from Ni to Ni0.2Mo0.8N, which weakens the binding strength of reaction intermediates, thereby boosting the catalytic performance. Relative to pure Ni, Ni‐Ni0.2Mo0.8N nanosheets show a lower overpotential of 83 mV at −10 mA cm−2 and good stability during 2,000 cycles for HER. Meanwhile, Ni‐Ni0.2Mo0.8N nanosheets exhibit an improved exchange current density for HOR with a 10.2‐fold enhancement in comparison with that of pure Ni. This work provides valuable insight into the reasonable design of efficient energy‐related electrocatalysts based on the tailoring of d‐band center by interface engineering.