Activating the lattice oxygen of low-cost Ni/WO2 nanoparticles on carbon paper for electrocatalytic oxidation of 2, 4-dichlorophenoxyacetic acid

Electrocatalysis is a promising method for removing harmful substances because it does not involve toxic agents and has low energy consumption. Herein, we have developed a low-cost nickel-tungsten dioxide (Ni/WO2) grown on carbon paper for the first time. Ni/WO2/CP demonstrates remarkable catalytic efficiency for the electrocatalytic oxidation of 2,4-dichlorophenoxyacetic acid (2,4-D), achieving a conversion rate of 100 % within 3 h and a total organic carbon (TOC) removal rate of 57 %. After four reaction cycles, the electrode can still achieve a conversion rate of 90.49 %. The exceptional activity of Ni/WO2 could be attributed to the activation of lattice oxygen in WO2 by coupled Ni, leading to the generation of a significant amount of superoxide free radicals (O-2(center dot-)) and creating numerous oxygen vacancies that serve as the active sites for subsequent 2,4-D oxidation. This work highlights the impact of lattice oxygen on electrocatalytic oxidation and material modification, offering a noble metal-free catalyst for converting harmful substances.