Multi-heterostructure with multi-interface for efficient hydrogen evolution reaction in industrial alkaline seawater

Abstract

The catalyst employed in industries for the hydrogen evolution reaction in seawater electrolyte suffers from scarcity, unsatisfactory catalytic activity and stability at large current density. To produce hydrogen under large current densities, the electrode requires both robust mechanical stability and high intrinsic catalytic activity. It remains challenging to create an electrode that ensures the exposure of catalytic sites while strengthening the binding force between the substrate and the catalyst, particularly in natural alkaline seawater electrolytes. In this work, the multi-heterostructure H₂–NiCo₂O₄@NiMoO₄ electrocatalyst with multi-interface was developed through a facile hydrothermal strategy, followed by a thermal reduction strategy. In 1 M KOH aqueous solution, the H₂–NiCo₂O₄@NiMoO₄ exhibited an overpotential of 216 mV at 1000 mA cm⁻² and a low Tafel slope of 29 mV dec⁻¹. Furthermore, a low Tafel slope of 31 mV dec⁻¹ and a current density of 1000 mA cm⁻² could be achieved with only 249 mV in seawater electrolytes (pH = 14). Remarkably, the H₂–NiCo₂O₄@NiMoO₄ electrocatalyst required only 445 and 345 mV to reach an ultra-high current density of 4000 mA cm⁻² in 1 M KOH and alkaline natural seawater electrolyte, respectively. Additionally, the H₂–NiCo₂O₄@NiMoO₄ electrocatalyst demonstrated excellent long-term stability of over 12 h in both 1 M KOH and alkaline seawater electrolyte. This work may pave a novel avenue for the development of excellent non-noble metal catalysts for hydrogen evolution reactions in industrial applications.