Exceptionally stable CePO4 and RuO2 contributing to catalytic oxidation of 1,2-dichloroethane on Co3O4 catalysts: Complete inhibition of chlorinated byproducts

Abstract

Highly toxic, reactive and refractory chlorinated VOCs (Cl-VOCs) is urgent for purification by the most favoured catalytic oxidation technique, however, the formation of polychlorinated byproducts is huge obstacle for most catalysts. Here, nanorods assembled monoclinic CePO4 microspheres were synthesized and used as the support of highly active but low-selective Co3O4 for catalytic oxidation of Cl-VOCs. The prepared Co3O4/CePO4 using ascorbic acid (AA) as a chelating agent presented a high activity and low selectivity of vinyl chloride (VC) for catalytic oxidation of 1,2-dichloroethane (DCE) due to the high dispersion of Co3O4, compared with bulk Co3O4 and Co3O4/SiO2, possible polychlorinated byproducts were completely inhibited in the presence of CePO4 support. The co-introduction of RuO2 further suppressed the formation of VC as a representative dechlorinated byproduct owing to the enhanced redox ability and migration of surface lattice oxygen, below 0.5% VC selectivity was detected on the optimized RuCoOx/CePO4 and completely disappeared above 275 °C. Moreover, RuCoOx/CePO4 also revealed the superior versatility, durability and thermal stability as well as the outstanding resistance to CO2, H2O and sulfur. The restraint of polychlorinated byproducts also can be achieved by other phosphates besides CePO4 and attributed to the strong coordination effect and electron-withdrawing function of PO43-. This work was contributed to further understand the inhibition of chlorinated byproducts for catalytic oxidation of Cl-VOCs and rationally design full-featured catalysts.