Self-supported Ni-NiWO4@NC heterojunction as high-efficient electrocatalyst for overall water splitting

Abstract

Industrial-scale hydrogen energy deployment requires the design of highly efficient catalysts with low overpotential and excellent stability, particularly at high current densities. We report a novel method for fabricating an N-doped carbon coated self-supporting Ni-NiWO4 heterojunction on a nickel foam (NF) catalyst (Ni-NiWO4@NC/NF) using a facile combination of hydrothermal and chemical vapor deposition techniques. The Ni-NiWO4@NC's plentiful catalytic active sites and their seamless contact with NF, along with the synergistic coupling of N-doped carbon, contribute to a decrease in charge transfer resistance and an improvement in catalyst stability. Impressively, when evaluated as an electrocatalyst in alkaline media, the overpotentials of Ni-NiWO4@NC/NF at a current density of 100 mA·cm−2 are only 125.6 mV for hydrogen evolution reaction (HER), and 308.8 mV for oxygen evolution reaction (OER), respectively. The catalyst also demonstrates exceptional stability for HER, OER, and water splitting at high current densities. In addition, the two-electrode electrolyzer using Ni-NiWO4@NC/NF as both cathode and anode need a cell voltage of 1.72 V to deliver 100 mA·cm−2. These findings offer valuable insights into the design and advancement of self-supported non-noble transition metal electrocatalysts for large-scale hydrogen production in industrial applications.