Polyoxometallate functionalizing CeO2 via redox-etching precipitation to synergistically catalyze oxidation of gaseous chlorinated pollutants: From lab to practice

Redox etching-precipitation is universally applied to homogeneously functionalize CeO2 with various acids including polyoxometallates (POMs) and liquid acids. Acid functionalization causes changes of physiochemical natures concerning reducibility, surface oxygen species as well as acidic sites. Among acids, because of POMs featuring superacid nature and Bronsted acid-induced antipoisoning effect, POMs-grafting can obviously facilitate catalytic oxidation of chlorinated organic contaminants (e.g. chlorobenzene, dichloromethane and trichloromethane) over CeO2-based catalysts. Through comparison, CeO2 nanorod functionalized with 5% silicotungstic acid (5% HSiW/r-CeO2) is screened out as an optimal catalyst, which exhibits a remarkable activity and long-term stability to catalyze oxidation of chlorinated pollutants at realistic condition. Moreover, the monolithic catalyst test pronounces that the practice application can be satisfied by loading 5% HSiW/r-CeO2 on honeycomb ceramics. With combination of structure and performance, the synergic effect of POMs functionalized CeO2 on catalytic oxidation of chlorinated pollutants is clearly refined.