Ordered Intermetallic PdFe₃N with Interstitial N Atoms on Porous Carbons for Efficient and Durable Hydrogen Production

Pd-based dual-metal site catalysts are active for the electrochemical water splitting for hydrogen production, while the slow hydrogen-binding ability and sluggish hydrolysis-dissociation kinetics of Pd-based catalysts limit their practical application. Assisting with the Gel-sol method, a complexation-gel strategy is proposed to synthesize ordered PdFe₃N transition metal nitrides on porous carbons (PdFe₃N TMNs/C) with the long-range ordered atomic arrangement, which accelerates water activation and dissociation. Moreover, interstitial N atoms in PdFe₃N TMNs/C induce charge dilution and redistribution at the dual-metal site, resulting in the optimization of the d-band centers and enhancing the bonding strength, which is efficient and durable for the hydrogen evolution reaction (HER). As a result, the prepared coating achieves overpotentials of only 45 mV for the HER at 10 mA cm⁻² in alkaline seawater electrolytes and exhibits excellent anion exchange membrane (AEM) performance and operates stably at a current density of 500 mA cm⁻² at 1.76 V for 100 h. This work presents a new perspective for synthesizing TMNs nanocrystals and promotes their application in bifunctional electrocatalysts.