In situ reconstruction of Ag-Ni2P on Ni foam as bifunctional electrocatalyst for acrylamide oxidation and hydrogen evolution

Concurrent remediation of organic pollutants in wastewater and energy-efficient hydrogen production is regarded as an attractive yet quite demanding dual strategy. Acrylamide (AA) is depolymerized from poly-acrylamide under harsh environmental conditions, such as exposure to UV radiation and elevated temperatures, causing severe water and soil pollution. Herein, in situ reconstructed Ag-doped Ni2P nanosheets on Ni foam (CV-Ag-Ni2P/NF) are developed as a bifunctional catalyst. This catalyst exhibits high activity for the AA oxidation reaction (AOR) and enables simultaneously energy-efficient electrolytic hydrogen evolution reaction (HER) processes. After cyclic voltammetry (CV) treatment, the previous zipper-like catalyst morphology transforms into a spherical morphology with interspersed rod-like structure particles on the surface, resulting in a unique structure with a larger electrochemical area and a higher quantity of active sites. The stability of CV-Ag-Ni2P/NF for both HER and AOR was established with chronopotentiometry tests. Post-characterizations by SEM, XRD and EDX analyses further suggest long-time stability of CV-Ag-Ni2P/NF. Particularly, the potential for AOR using CV-Ag-Ni2P/NF is minimized to 1.82 V generating a current density of 100 mA cm2 in the two-electrode setup. Significantly, 79.3% of AA was removed after 24 h of AOR processing at 50 mA cm2. Simultaneously, the ethanol generated at the anode serves as a value-added product for industrial application. Density functional theory (DFT) calculations demonstrate that the Ag atoms act as the active sites for the degradation of AA to produce ethanol in the hybrid structure, while the Ag atoms exhibit a more thermoneutral value for *H2O and AA adsorption. The coupling of AA oxidation with H2 production in a single system can efficiently reduce energy consumption during the treatment of AA in aqueous solutions, while generating high-value products.