Plasma-modified cerium oxide nanocatalyst for atmospheric pressure plasma degradation of methylene blue

A novel approach in the field of heterogeneous catalysis is presented in this research, focusing on organic compound degradation using CeO2. The catalyst was activated with plasma, producing active oxygen species from the water medium. CeO2 nanoparticles were synthesized using the chemical precipitation method and modified by a plasma treatment at atmospheric pressure. The untreated and plasma-treated nanostructures were analyzed using UV-VIS, Raman XRD, XPS spectroscopy, and TEM. The CeO2 Band Gap was modified with plasma from 3.31 eV to 2.85 eV. Raman and XRD spectroscopy found defects in the crystal lattice caused by oxygen vacancies, affecting the CeO2 surface reduction of Ce4+ to Ce3+. XPS confirmed the Ce3+ content of 10 % to 18.5 % for untreated and plasma-treated CeO2, respectively. The percentage of degradation at 30 min was 50 % using plasma, 80 % in synergy with CeO2, and 90 % with CeO2 modified with plasma, indicating that the increase in degradation in the first minutes is due to the decomposition of H2O2 in their CeO2 active sites.