Enhanced performances in catalytic oxidation of o-xylene over hierarchical macro-/mesoporous silica-supported palladium catalysts  

作　　者：Nanli QIAO Xin ZHANG Chi HE Yang LI Zhongshen ZHANG Jie CHENG Zhengping HAO 

机构地区：[1]Department of Environmental Nano-materials and Technologies, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China [2]Department of Environmental Science and Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China

出　　处：《Frontiers of Environmental Science & Engineering》2016年第3期458-466,共9页环境科学与工程前沿（英文）

基　　金：This work was financially supported by the National Natural Science Foundation （Grant Nos. 21337003 and 21477149）, and the Strategic Priority Research Program of the Chinese Academy of Sciences （XDB05050200）.

摘　　要：A series of hierarchical macro-/mesoporous silica supports （MMSs） were successfully synthesized using dual-templating technique employing polystyrene （PS） spheres and the Pluronic P123 surfactant. Pd was next loaded on the hierarchical silica supports via colloids precipitation method. Physicochemical properties of the synthesized samples were characterized by various techniques and all catalysts were tested for the total oxidation of o-xylene. Among them, the Pd/MMS-b catalyst with tetraethoxysilane/polystyrene weight ratio of 1.0 exhibited superior catalytic activity, and under a higher gas hourly space velocity （GHSV） of 70000 h^-1, the 90% conversion of o-xylene has been obtained at around 200℃. The BET and SEM results indicated that Pd/MMS- b catalyst possesses high surface area and large pore volume, and well-ordered, interconnected macropores and 2D hexagonally mesopores hybrid network. This novel ordered hierarchical porous structure was highly beneficial to the dispersion of active sites Pd nanoparticles with less aggregation, and facilitates diffusion of reactants and products. Furthermore, the Pd/MMS-b catalyst possessed good stability and durability.A series of hierarchical macro-/mesoporous silica supports （MMSs） were successfully synthesized using dual-templating technique employing polystyrene （PS） spheres and the Pluronic P123 surfactant. Pd was next loaded on the hierarchical silica supports via colloids precipitation method. Physicochemical properties of the synthesized samples were characterized by various techniques and all catalysts were tested for the total oxidation of o-xylene. Among them, the Pd/MMS-b catalyst with tetraethoxysilane/polystyrene weight ratio of 1.0 exhibited superior catalytic activity, and under a higher gas hourly space velocity （GHSV） of 70000 h^-1, the 90% conversion of o-xylene has been obtained at around 200℃. The BET and SEM results indicated that Pd/MMS- b catalyst possesses high surface area and large pore volume, and well-ordered, interconnected macropores and 2D hexagonally mesopores hybrid network. This novel ordered hierarchical porous structure was highly beneficial to the dispersion of active sites Pd nanoparticles with less aggregation, and facilitates diffusion of reactants and products. Furthermore, the Pd/MMS-b catalyst possessed good stability and durability.

关 键 词：hierarchical macro-/mesoporous silica palladium VOCs catalytic oxidation 

分 类 号：O643.36[理学—物理化学] O613.72[理学—化学]