Accelerating Neutral Hydrogen Evolution with Tungsten Modulated Amorphous Metal Hydroxides

Abstract

Developing efficient, low-cost, and biocompatible electrocatalysts toward hydrogen evolution reaction (HER) in neutral environments is vital to the development of a hybrid water splitting–biosynthetic system to achieve high-efficiency solar-to-fuels conversion. We report here a strategy to improve the sluggish HER kinetics on 3d transition-metal hydroxides by incorporating tungsten through a one-step electrodeposition method. The prepared amorphous CoW(OH)x delivers high HER activity in neutral solution, which only requires overpotentials of −73.6 and −114.9 mV to achieve the current densities of −10 and −20 mA cm–2 in 1.0 M phosphate buffer solution (PBS), respectively. The activity can be ascribed to the synergistic effects between Co and W, where Co sites facilitate H2O dissociation to generate Had intermediates and W sites could effectively convert Had to H2. Meanwhile, the amorphous architecture features homogeneously dispersed Co and W atoms that avoid crystalline phase separation, further strengthening their collaborative interactions. Similar enhanced HER activity is also observed on the electrodeposited NiW(OH)x electrocatalyst, suggesting the universality of this strategy for accelerating HER in neutral environments.