Yaping Zhang,Guobo Li,Peng Wu,Hongqiang Yang,Sheng Wang,Kai Shen,Ling Wang
TiO 2 -Vo support with abundant oxygen vacancy was prepared by hydrothermal method, purchased TiO 2 -P for comparison, and Pd 0.12 V 4 /TiO 2 catalysts with different TiO 2 structures were prepared to investigate catalytic oxidation for dichloromethane (DCM). Pd 0.12 V 4 /TiO 2 -Vo catalyst showed excellent low temperature DCM removal efficiency, T 90 of which reduced to 290 ℃, and Cl resistance was maintained in 40 h. Abundant oxygen vacancy of TiO 2 -Vo was formed in transformation process of part anatase TiO 2 to rutile phase. The obtained Pd 0.12 V 4 /TiO 2 -Vo catalyst possessed rich acid sites, higher adsorbed oxygen (O ads ) ratio and better oxygen mobility, which inhibited loss of active components and improved DCM removal efficiency. DCM removal efficiency of Pd 0.12 V 4 /TiO 2 catalyst was reduced by HCl, while negative effect in the way of weakening competitive adsorption between HCl and DCM, that would be reduced by TiO 2 supports modification. The present work is favorable for further DCM removal catalyst anti-Cl poisoning modification and application in manufacture industry.
Controlling chlorobenzene (CB) and NO x emissions via catalytic oxidation and selective catalytic reduction necessitates high redox performance catalysts, and construction of active centers with multiple adsorption centers towards reactants is prerequisite for developing such catalysts. Herein, the electronic structure and active centers of the PdV/TiO 2 bimetallic catalyst were modulated by Sb modification. The neighboring antimony (Sb) promoted the charge transfer between V and Pd centers, and suppressed the adsorption of SO 2 on active sites, thus accelerating CB/NO x conversion and significantly avoiding the deposition of sulfur species on the active centers, especially the Pd species. The detailed plausible CB/NO x catalytic removal pathway (CB free → CB ads → C 6 H 5 ads + Cl ads + O species (O latt and O ads ) → C x H y O z + Cl ads + Brønsted → CO 2 + H 2 O + HCl on SbPdV/TiO 2 catalyst surface was further established. This research provided a strategy for the development of improved CB catalytic oxidation + selective catalytic reduction (CBCO + SCR) catalysts by tuning the electronic structure of active centers.
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