Highly levels of atomically dispersed Ru atom on CeO2 from defects designing for promoted catalytic oxidation of chlorobenzene

• High level of atomically dispersed Ru/CeO 2 catalysts were synthesized through defective designing method. • The dispersity and bonding energy were significantly increased. • The chemically adsorbed oxygen and Brønsted acid sites were simultaneously enhanced. • Catalysts for CB removal present excellent low-temperature activity and long-term durability. Compared to noble metal catalysts at the nanoscale, single-atom catalysts are more likely to be poisoned then lead to the loss of activity during the catalytic oxidation of chlorinated volatile organic compounds (CVOCs) due to their unique coordination environment. Additionally, the commonly used low loading single-atom catalysts often suffer from limited active sites and low catalysts activities. Therefore, it is of great significance to synthesize stable and high-loading single-atom catalysts for CVOCs oxidation. In this study, a highly loaded (2.4 wt%) atomically dispersed 4RuCeO 2 -AA catalyst was synthesized through defect designing for the catalytic combustion of chlorobenzene (CB). By introducing defect sites on the CeO 2 supports using ascorbic acid, more atomically dispersed Ru were strongly anchored, significantly increasing the number of active sites and oxygen vacancies. With the same noble metal contents, the 4RuCeO 2 -AA catalyst exhibited superior performance in both CO 2 selectivity (99.6 % at 240 °C) and catalytic stability (no decay for 20 h). This enhanced performance can be attributed to the high dispersion of RuO x , strong Ru-O-Ce bonding energy, and an increased of chemically adsorbed oxygen, as well as the presence of strong Brønsted acid sites.