Synthesis of porous biomorphic Cu/CeO 2 /Al 2 O 3 by using cotton as templates
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1148-PP08-13
Synthesis of porous biomorphic Cu/CeO2/Al2O3 by using cotton as templates Ka Lok Chiu1, Fung Luen Kwong1, Juncai Jia2, Jia Li3 and Hang Leung Ng1 Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong, China. 2 Department of Chemistry, The Chinese University of Hong Kong, Shatin, Hong Kong, China. 3 School of Material Science and Engineering, University of Jinan, Jinan, Shandong, China. 1
ABSTRACT Porous biomorphic Cu/CeO2/Al2O3 was synthesized successfully via an impregnation and calcinations method with cotton as template. To prepare the sample, cotton ball was soaked in an AlOOH, Cu(NO3)2 and Ce(NO3)2 mixture before being dried and calcined in air at the temperatures ranged from 400 to 800 oC. Thereafter, the sample was further reduced with diluted hydrogen. The structure of the product was found to resemble to that of the cotton except that many of the fibers became hollow. The cotton-like product after calcinations contained Cu, CeO2, and Al2O3.The grain size of the components were determined to be from 5 to 20 nm. The BET surface area of this Cu/CeO2/Al2O3 product is estimated to be about 107 m2/g. The product was thermally stable up to 700 oC. INTRODUCTION To ease the global demands for fossil fuels and to lower their harmful emissions to environment, proton exchange membrane fuel cell using hydrogen (H) fuel is being actively considered for automotive applications [1, 2]. To overcome the technical problems associated with H storage and distribution, one promising solution is the on-board production of H2 using methanol as a supplier. Methanol, via the steam reforming process, can produce H2 and CO2 in a molar ratio of 3:1, and less than 1 mol% of CO as a by-product [3]. However, in fuel cell, even trace of CO (~10 ppm) in the reformed gases can deteriorate the electrode and lead to poor cell performance [4]. The elimination of CO from the H2-rich gases is traditionally handled by catalysts using platinum [5] or gold [6] on supports such as stainless steel, alumina, silica, or zeolite [7]. In recent years, this practice has been moved forward using less expensive Cu or its oxide on ceramic substrates. The Cu-Ce-Al ternary metal oxides have demonstrated effective catalysis in this type of application. A large number of studies have been conducted for understanding the properties of Cu/Ce/Al oxides catalysts and improving their performances in catalytic reactions [4, 8, 9]. Undoubtedly, the particle size, the dispersion of active species, and the specific surface area in the catalyst are closely related to the catalytic activity, yield and selectivity. In this regard, we have recently synthesized a new type of Cu/CeO2/Al2O3 product via a biomorphic approach using cotton as template. Among many organic template, cotton is one of the most suitable candidates. It is cellulose-based with pores and vessels in nanometer-size [10]. Its threedimensional fibrous structure allows gases to pass through easily. The Cu/CeO2/Al2O3 product can be a potential candidate for the rapid methan
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