A new strategy to improve catalytic activity for chlorinated volatile organic compounds oxidation over cobalt oxide: Introduction of strontium carbonate

Abstract

Co3O4–SrCO3 catalysts with various Sr/Co ratios were synthesized by the coprecipitation method, and their properties were tuned by adjusting the Sr/Co molar ratio. Furthermore, the catalytic combustion of vinyl chloride (VC) was used to evaluate the catalytic activity of the Co3O4–SrCO3 catalysts. The physicochemical properties of the catalysts were studied by X-ray diffraction (XRD), infrared spectroscopy (IR), N2 sorption, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), H2 temperature-programmed reduction (H2-TPR) and VC temperature-programmed desorption (VC-TPD). The results showed that the Co3O4–SrCO3 catalysts exhibited composite phases of Co3O4 and SrCO3 and the presence of interactions between them. As a result, the crystallization of the Co3O4 phase for the Co3O4–SrCO3 catalysts was restrained, and the state of Co on the catalyst surface was adjusted. Furthermore, the reducibility and VC adsorption capacity of the Co3O4–SrCO3 catalysts with Sr/Co molar ratios of 0.2 and 0.4 were enhanced compared with those of the Co3O4 catalyst. Otherwise, catalyst SrCo-0.4 exhibited excellent catalytic performance, accompanied by the highest reaction rate and the lowest apparent activation energy. More importantly, the optimized SrCO3–Co3O4 catalyst showed superior catalytic performance compared with other transition metal oxides in previous literature. These results brought a new idea for promoting the activity of transition metal catalysts for the deep oxidation of chlorinated volatile organic compounds (CVOCs) by introducing alkaline-earth metal salts.