LAUSR

Abstract Enriching electrocatalysts with uncommon definite functions are of great influence but remains extraordinarily challenging. Upon the excellent metallic characteristics of transition metal nitrides (TMN), the unfavorable d-band energy level severely hinders their hydrogen evolution reaction (HER) catalytic properties. Herein, a new concept termed “enhanced metallicity” is introduced to address this issue. We strongly enable bimetallic Ni2Fe2N with outstanding alkaline HER capability by making more metallic through in situ hybridization of another bimetallic compound, Ni3Fe. The enhanced metallicity Ni2Fe2N/Ni3Fe hybrid displays nearly 200% enhancement in alkaline HER catalytic activity compared to pristine Ni2Fe2N at a current density of 10 mA cm-2. Experimental and theoretical analyses, as well as crystal field diagram persistently show that the enhanced HER catalytic properties is attributed to the enhanced metallic nature and synergistic effect, endowing strong electronic interaction between Ni2Fe2N and Ni3Fe. The strong electronic interaction enables low adsorption energy and a reasonable shift in the d-orbital, which helps in facilitating water dissociation and H-desorption. This present study offers a useful pathway for the rational design of other catalysts for HER and beyond.