Heterointerface-Rich Ni3N/WO3 Hierarchical Nanoarrays for Efficient Glycerol Oxidation-Assisted Alkaline Hydrogen Evolution

Graphical Heterostructure Ni 3 N/WO 3 nanosheet arrays loaded on nickel foam (Ni 3 N/WO 3 /NF) were synthesized by combining cation-exchange with the hydrothermal method and annealing under an ammonia atmosphere (NH 3 ). Ni 3 N/WO 3 nanosheet arrays consist of irregular particles and have abundant active sites due to the heterogeneous interface between Ni 3 N and WO 3 . Ni 3 N/WO 3 /NF was used for efficient electrocatalytic glycerol oxidation coupled to hydrogen production. Glycerol oxidation-assisted water electrolysis has emerged as a cost-effective way of co-producing green hydrogen and HCOOH. Still, preparing highly selective and stable nickel-based metal electrocatalysts remains a challenge. Herein, heterostructure Ni 3 N/WO 3 nanosheet arrays of bifunctional catalysts with large specific surface areas loaded on nickel foam (denoted as Ni 3 N/WO 3 /NF) were synthesized. This catalyst was for glycerol oxidation reaction (GOR) and hydrogen evolution reaction (HER) with excellent catalytic performance, a voltage saving of 267 mV compared to oxygen evolution reaction (OER), and a HER overpotential of 104 mV at 100 mA cm −2 . The cell voltage in the assembled GOR//HER hybrid electrolysis system reaches 100 mA cm −2 at 1.50 V, 296 mV lower than the potential required for overall water splitting. This work demonstrates that replacing GOR with OER using a cost-effective and highly active Ni-based bifunctional electrocatalyst can make hybrid water electrolysis an energy-efficient, sustainable, and green strategy for hydrogen production.