Electrochemical Generation of Hydrogen Peroxide Using Cerium Oxide Nanostructures Supported on Graphene: Synthesis, Characterization, and Application in Wastewater Treatment

Abstract

This study investigates the electrochemical generation of hydrogen peroxide (H₂O₂) using three distinct cerium oxide nanostructures—nanorods, nanospheres, and nanoparticles—supported on graphene. The nanorods and nanospheres were synthesized via the hydrothermal method, with controlled adjustments to centrifugation speed, calcination temperature, and duration to tailor their morphology. Cerium nanoparticles were prepared using a coprecipitation method. These nanostructures were employed to modify graphene and were evaluated for their performance in H₂O₂ electrogeneration. Among them, cerium nanorods exhibited the highest H₂O₂ production, achieving a 91% efficiency. This superior performance can be attributed to the presence of oxidizing species (Ce³⁺), as identified through Raman spectroscopy, along with oxygen vacancies and enhanced surface hydrophilicity. Scanning electron microscopy (SEM) revealed that the nanorods were optimally distributed below the graphene sheets. The hydrothermal and coprecipitation synthesis methods proved effective for producing cerium oxide nanostructures with high catalytic activity. These findings highlight the potential of cerium oxide nanostructures as efficient catalysts for wastewater treatment via the electro-Fenton process.