Ni-Co-6–4 catalyst with crystalline-amorphous interfaces for efficient hydrazine electrooxidation

The interfacial electron interactions in heterogeneous catalysts are critical determinants of their catalytic efficiency. In this study, a Ni-Co alloy coating with a precisely controlled Ni/Co of 6:4 was synthesized on nickel foam (denoted as Ni-Co-6–4/NF) using NaH 2 PO 2 as a reducing agent. The resulting surface exhibited negligible phosphorus incorporation. The Ni-Co-6–4 coating featured a unique crystalline-amorphous interfacial structure. As expected, Ni-Co-6–4/NF demonstrated outstanding catalytic activity toward hydrazine oxidation, achieving a current density of 169.1 mA·cm −2 at 0.3 V versus the reversible hydrogen electrode (RHE) without i R compensation. Moreover, it maintained 100 % of its catalytic performance over 24 h of continuous electrolysis, placing it among the most durable non-noble Ni-based electrocatalysts reported for hydrazine oxidation. Density functional theory (DFT) calculations revealed that this improved performance stems from electron redistribution at the crystalline-amorphous interface, which enhances N 2 H 4 adsorption. These findings highlight the effectiveness of crystalline-amorphous interface engineering as a powerful strategy for the rational design and optimization of high-performance electrocatalysts.