Micro-meso hierarchical ZSM-5 zeolite supported RuOx nanoparticles for activity enhancement of catalytic vinyl chloride oxidation

Abstract

Hierarchical ZSM-5 zeolites were synthesized by an alkali hydrothermal treatment strategy and adopted as support materials for the fabrication of RuOx nano catalysts. The physicochemical properties and catalytic activities for vinyl chloride (VC) oxidation over the resultant RuOx/HZ5-nd (n = 2, 3, 4) catalysts were successfully modulated by the treatment time regulation (2d, 3d and 4d) of ZSM-5 solid. Experimental results demonstrated that the RuOx/HZ5-nd catalysts possessed notable cavity-shell structures with micro-meso hierarchical porosity, which brought about the increased specific surface area, the enhanced low-temperature reducibility and the strengthened surface acidity comparable to RuOx/HZ5. All these superiorities were recognized as the crucial origin for boosting catalytic oxidation of VC. Especially, the RuOx@HZ5-3d catalyst exhibited the optimum VC oxidation activity with the lowest T50 and T90 (temperature at 50 and 90% conversion) of 275 and 297 °C, which was 22 and 24 °C lower than those of RuOx/HZ5. Importantly, RuOx@HZ5-3d exhibited significantly high thermal stability, water resistant and regeneration capacity from humid conditions, which made it a promising material for the catalytic purification of chlorinated volatile organic compounds.