Interfacial electron-engineered tungsten oxynitride interconnected rhodium layer for highly efficient all-pH-value hydrogen production

Abstract

Designing and synthesizing eco-friendly and efficient catalysts for the hydrogen evolution reaction (HER) plays a crucial role in the field of large-scale and high-purity hydrogen production. However, it is severely hampered by the sluggish kinetics of the water dissociation step in non-acidic media. To optimize catalytic kinetics, interfacial electron engineering between active sites and supports has been regarded as an essential strategy to achieve compelling electrocatalytic all-pH-value-hydrogen production. Herein, we present the successful fabrication of WNO-coupled Rh layers (Rh–WNO) by a simple thermal treatment of a urea sol–gel with mixed W and Rh salts. This facile one-pot synthetic method is easy to scale up and the resulting Rh–WNO catalyst features Rh nanoclusters anchored on the surface of the well-ordered WNO crystals via Rh–N and Rh–O bonds. The optimal catalyst, Rh–WNO, delivered low overpotentials of 19, 22, and 134 mV at a current density of 10 mA cm⁻² in 0.5 M H₂SO₄, 1.0 M KOH, and 1.0 M PBS, respectively. Notably, Rh–WNO exhibits a high turnover frequency (TOF) of 7.84 H₂ s⁻¹ in alkaline conditions, which is much higher than those of Pt/C (0.9 H₂ s⁻¹), Rh/C (0.77 H₂ s⁻¹), and most of the reported HER electrocatalysts. This work may provide an effective and economic approach for scaling up the production of highly efficient and stable metal nitride-based HER catalysts.