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Constructing a Built-In Electric Field To Accelerate Water Dissociation for Efficient Alkaline Hydrogen Evolution.

Shuai NiuJiawei WangYanqiu WuJuan ZhangXu WuHao LuoWen-Jie Jiang
Published in: ACS applied materials & interfaces (2024)
The alkaline hydrogen evolution reaction (HER) is intricately linked to the water dissociation kinetics. The quest for new strategies to accelerate this step is a pivotal aspect of enhancing the HER performance. Herein, we designed and synthesized a heterogeneous nickel phosphide/cobalt phosphide nanowire array grown on nickel foam (Ni 2 P/CoP/NF) to form a p-n junction structure. The built-in electric field (BEF) in the p-n junction optimizes the binding ability of hydrogen and hydroxyl intermediates, efficiently promoting water dissociation for the alkaline HER. Consequently, Ni 2 P/CoP/NF exhibits a lower overpotential of 58 and 118 mV at 30 and 100 mA cm -2 , respectively, and high stability over 40 h at 300 mA cm -2 for the HER in 1 M KOH. Computational calculations combined with experiment results testify that the BEF presence in the p-n junction of Ni 2 P/CoP/NF effectively promotes water dissociation, regulates intermediate adsorption/desorption, and boosts electron transport. This study presents a rational design approach for high-performance heterogeneous electrocatalysts.
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