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, Ni 3 P 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 NO 3 - concentration and pH. Presence of chlorine induced electrochlorination will tune N 2 (selectivity up to ∼100 %) to become the dominant products. Mechanism study suggested that the atomic H*-mediated indirect reduction, meanwhile properties of Ni 3 P to strengthen NO 3 - adsorption and prevent desorption of NO and NO 2 are responsible for the enhancement of nitrate reduction. This work is meaningful for water environment protection and energy sustainable development. • Nitrate reduction rate constant was enhanced 20–40 fold after loading Ni 3 P on nickel foam cathode. • A high ammonia selectivity of 99 % was achieved in absence of chlorine. • N 2 selectivity reached 100% under the action of electrochlorination. • The atomic H*-mediated indirect reduction played a role in nitrate electrochemical reduction. • The Ni 3 P particles can enhance NO 3 - adsorption and inhibit desorption of NO and NO 2 .