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Accelerating Neutral Hydrogen Evolution with Tungsten Modulated Amorphous Metal Hydroxides

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journal contribution
posted on 02.05.2018, 00:00 by Le Zhang, Peng Fei Liu, Yu Hang Li, Chong Wu Wang, Meng Yang Zu, Huai Qin Fu, Xiao Hua Yang, Hua Gui Yang
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.