Ce_1–x Co _x O₂ Nanorods Prepared by Microwave-Assisted Hydrothermal Method: Novel Catalysts for Removal of Volatile Organic Compounds

In this study, nanorods of a Ce_{1– x} Co _x O₂ system, with x = 0, 0.05, 0.10, 0.15 and 0.20, were synthesized employing a microwave-assisted hydrothermal method and their catalytic activity in the total oxidation of three VOCs (benzene, toluene and o-xylene) was investigated. The physicochemical characterization showed that the inclusion of cobalt led to an increase in the oxygen vacancies in the system. Also, an increase in the catalytic activity was observed with the progressive incorporation of cobalt into the ceria matrix. The results revealed that the Ce_0.80Co_0.20O₂ catalyst was able to remove 100% of the benzene, nearly 100% of the toluene and around 70% of the o-xylene. Increasing the amount of oxygen vacancies could result in an enhancement of the bulk and surface oxygen mobility. The higher oxidation activity observed for the catalyst with the highest cobalt load can be attributed to a combination of several factors, including a greater number of active sites of the cobalt being exposed and greater mobility of the active oxygen species.