Electrodeposition of dense spherical Ni₃P on nickel foam cathode enhance nitrate electrochemical reduction via promoting nitrate adsorption

Electrochemical nitrate reduction to nitrogen gas is considered as an alternative strategy to address water pollution problem, but the high cost and poor product selectivity of electrode limit its application. Here, Ni₃P loaded nickel foam was fabricated via one-step eletrodeposition as cathode for electrochemical nitrate reduction. Due to the improvement of electron transfer rate and electrochemically active surface area, current efficiency and reaction rate constant enhanced 20.4-flod and 40-fold, respectively. Batch experiments revealed the remarkable nitrate reduction performance (∼97.53 %) after the optimization of potential, initial NO₃^- concentration and pH. Presence of chlorine induced electrochlorination will tune N₂ (selectivity up to ∼100 %) to become the dominant products. Mechanism study suggested that the atomic H*-mediated indirect reduction, meanwhile properties of Ni₃P to strengthen NO₃^- adsorption and prevent desorption of NO and NO₂ are responsible for the enhancement of nitrate reduction. This work is meaningful for water environment protection and energy sustainable development. © 2024