Nanoporous Nickel Cathode with an Electrostatic Chlorine-Resistant Surface for Industrial Seawater Electrolysis Hydrogen Production

Abstract

Seawater electrolysis presents a promising avenue for green hydrogen production toward a carbon-free society. However, the electrode materials face significant challenges including severe chlorine-induced corrosion and high reaction overpotential, resulting in low energy conversion efficiency and low current density operation. Herein, we put forward a nanoporous nickel (npNi) cathode with high chlorine corrosion resistance for energy-efficient seawater electrolysis at industrial current densities (0.4−1 A cm −2 ). With the merits of an electrostatic chlorine-resistant surface, modulated Ni active sites, and a robust threedimensional open structure, the npNi electrode showed a low hydrogen evolution reaction overpotential of 310 mV and a high electricity−hydrogen conversion efficiency of 59.7% at 400 mA cm −2 in real seawater and outperformed most Ni-based seawater electrolysis cathodes in recent publications and the commercial Ni foam electrode (459 mV, 46.4%) under the same test condition. In situ electrochemical impedance spectroscopy, high-frame-rate optical microscopy, and first-principles calculation revealed that the improved corrosion resistance, enhanced intrinsic activity, and mass transfer were responsible for the lowered electrocatalytic overpotential and enhanced energy efficiency.

Recycled Cathodes in Rechargeable Aqueous Batteries as Ready-Made Electrodes for Oxygen Evolution Catalysis

“…Water electrolysis has long been regarded as a key technology to produce green hydrogen fuels in the near future. − However, the sluggish kinetics of oxygen evolution reaction (OER) results in the large overpotential and low energy conversion efficiency of water-splitting reactions. − RuO 2 materials are by far the state-of-the-art catalysts to drive the OER, but the resource scarcity of noble metals has restricted their applications in large scale. − Instead, low-cost MnO 2 materials with high electronic and crystal structure tunability have been widely studied, especially in the field of electrocatalysis and batteries. − Nevertheless, developing a highly efficient MnO 2 electrode with an OER performance comparable to that of RuO 2 remains a grand challenge.…”