Electrocatalytic Degradation of Methyl Orange Using ZnO/Boron‐Doped Diamond Nanocomposite

ABSTRACT

ZnO/BDD nanocomposites were synthesized and evaluated as advanced electrocatalysts for the degradation of methyl orange (MO). XRD analysis confirmed the successful incorporation of ZnO crystallites into the BDD matrix, resulting in reduced crystallite size, lower lattice strain, and improved surface properties compared to the pristine materials. Electrochemical characterization using cyclic voltammetry (CV) revealed a significant enhancement in the electrochemically active surface area (ECSA) after compositing. The calculated ECSA of the ZnO electrode was 0.0298 cm ² , while the ZnO/BDD electrode reached 0.0605 cm ² , corresponding to an approximately 2.03‐fold increase. This improvement provides a larger number of electroactive sites for interfacial reactions. Electrocatalytic degradation tests demonstrated a strong synergistic effect between ZnO and BDD. BDD promoted continuous hydroxyl radical (OH) generation through advanced oxidation processes, whereas ZnO enhanced dye adsorption and stabilized •OH radicals via surface oxygen vacancies. Consequently, the ZnO/BDD nanocomposite exhibited a higher degradation than the individual electrodes. The degradation mechanism involved sequential •OH attacks on azo bonds, sulfonate groups, and aromatic rings of MO, leading to fragmentation and eventual mineralization into CO ₂ and H ₂ O. These results highlight the ZnO/BDD nanocomposite as a promising electrode material for wastewater treatment.