Crystalline Cobalt/Amorphous LaCoOx Hybrid Nanoparticles Embedded in Porous Nitrogen-Doped Carbon as Efficient Electrocatalysts for Hydrazine-Assisted Hydrogen Production

Abstract

Hydrazine electro-oxidation has received substantial attention owing to its high energy density, low onset potential and wide applications in hydrazine-assisted hydrogen production and direct hydrazine fuel cells (DHFC). In this work, crystalline cobalt/amorphous LaCoOx hybrid nanoparticles embedded in porous nitrogen-doped carbon (N-C) were fabricated via pyrolytic decomposition of the dual-metal lanthanum-incorporated zeolitic-imidazolate framework (La/ZIF-67), which exhibit high activity and stability towards electrocatalytic hydrazine oxidation reaction (HzOR). The hybrid nanoparticles based on metallic cobalt and amorphous LaCoOx could provide abundant active sites for HzOR catalysis, while the highly conductive and porous N-C could act as both robust skeleton for anchoring the active hybrid nanoparticles and facile charge transport pathway for HzOR process, thereby resulting in enhanced HzOR activity. With the synergistic merits of enriched active sites, large surface area, enhanced charge transfer ability and intimate catalyst anchoring, promoted HzOR performance with high activity and stability was achieved for the optimized catalyst, which shows ultralow onset potential of -0.17 V vs. RHE, high HzOR current density of 69.2 mA cm-2 at 0.3 V vs. RHE and superior stability for 20 h continuous catalysis, making the catalyst a promising electrode material for hydrazine-assisted hydrogen production.