Chemical upcycling of Ni from electroplating wastewater into a well-defined catalyst for electrooxidation of glycerol to formate

Abstract

Highly effective and efficient remediation of hazardous Ni waste from electroless electroplating wastewater remains a significant challenge. However, rather than regarding it as hazardous waste, Ni-electroplating wastewater can instead be considered a huge resource of Ni. Herein, we report a convenient hydrothermal strategy for upcycling Ni from nickel-electroplating wastewater into a carbon-doped Ni–P alloy (denoted as C/Ni–P_x) electrocatalyst for the oxidation of glycerol to formate. This strategy can reduce the total Ni²⁺ concentration from thousands of milligrams per liter to lower than the advisory level of discharge standards for electroplating effluent in China (≤0.5 mg L⁻¹), demonstrating an excellent nickel uptake capacity and potential for practical application in both simulated and actual Ni-electroplating wastewater. Furthermore, the resultant C/Ni–P_x exhibited good electrooxidation of glycerol to formate with a selectivity of 96.4%, surpassing a vast majority of previously reported electrocatalysts. Therefore, our findings not only provide an efficient strategy for removing Ni from electroless electroplating wastewater but also advance the upcycling of Ni waste into a functional material for the electrocatalytic synthesis of value-added products.