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二氧化碳加氢直接合成二甲醚催化剂的研究 Ⅱ 铜/锌对复合催化剂结构和性能的影响
引用本文:赵彦巧,陈吉祥,张建祥,张继炎.二氧化碳加氢直接合成二甲醚催化剂的研究 Ⅱ 铜/锌对复合催化剂结构和性能的影响[J].燃料化学学报,2005,33(3):334-338.
作者姓名:赵彦巧  陈吉祥  张建祥  张继炎
作者单位:天津大学化工学院,催化科学与工程系,天津,300072
摘    要:制备了具有不同铜/锌(氧化物质量比)的CuO-ZnO-Al2O3/HZSM-5复合型催化剂,考察了其对CO2加氢直接合成二甲醚的催化性能,并采用H2-TPR、XRD、BET、IR及XPS等表征方法对催化剂的物化性质进行了表征。结果表明,催化剂中的铜/锌对催化剂的反应性能、晶相结构以及还原难易程度等均有一定程度的影响。在所制备的四种不同铜/锌的复合催化剂中,以Cu/Zn=1/2的催化剂反应性能最为理想,虽然它们的还原峰位置和比表面积相差不大,但在反映催化剂各组分问相互作用的IR谱图中则表现出较明显的差别。XPS结果表明,活性组分铜以Cu^ 和Cu^0两种形态存在,支持Cu^ 和Cu^0共同组成合成甲醇活性中心的观点。

关 键 词:二氧化碳  加氢  二甲醚  CuO-ZnO-Al2O3/HZSM-5催化剂  铜/锌
文章编号:0253-2409(2005)03-0334-05
收稿时间:2004-09-02
修稿时间:2004年9月2日

Study on direct synthesis of dimethyl ether by hydrogenation of carbon dioxide Ⅱ Effects of Cu/Zn ratio on structure and properties of catalysts
ZHAO Yan-qiao,CHEN Ji-xiang,ZHANG Jian-xiang,ZHANG Ji-yan.Study on direct synthesis of dimethyl ether by hydrogenation of carbon dioxide Ⅱ Effects of Cu/Zn ratio on structure and properties of catalysts[J].Journal of Fuel Chemistry and Technology,2005,33(3):334-338.
Authors:ZHAO Yan-qiao  CHEN Ji-xiang  ZHANG Jian-xiang  ZHANG Ji-yan
Abstract:In order to systemically investigate the effects of Cu/Zn ratio on physical-chemical properties and catalytic performance of catalyst, a series of CuO-ZnO-Al_2O_3/HZSM-5 composite catalysts with different Cu/Zn ratios (Cu/Zn=1/2;4/5;5/4 and 2/1, weight ratio of oxides) were prepared. And their catalytic performance for hydrogenation of CO_2 was evaluated in a laboratory fixed-bed reactor system. The physical-chemical properties of these catalyst samples were also studied by means of H_2-TPR, XRD, BET, IR and XPS. The results showed that Cu/Zn ratio in catalyst could affect the catalytic activity, the crystal phase structure and the reduction property of the catalyst to a certain extent. Among the concerned catalysts with different Cu/Zn ratios, the catalyst with Cu/Zn=1/2 showed better catalytic performance for dimethyl ether and methanol synthesis. The TPR profiles of different catalysts showed some difference. With the increase of Cu content, the areas of the reduction peaks increased and the reductive peak temperature decreased slightly. The XRD results indicated that the degree of copper dispersion was decreased with the increase of Cu content in the catalysts. There was no evident difference between the catalysts in BET specific surface areas, and there was also no obvious relation between BET specific surface area and catalytic performance. The IR results of the catalysts presented that there was a corresponding relation between the catalytic activity and the intensity of absorption peak at 1 101 cm -1, which indicated the interaction between the metal oxides and HZSM-5. The XPS characterization proved that the active sites could be in two forms, i.e., Cu+ and Cu0, which supported the viewpoint that the Cu+ and Cu0 both were active species during methanol synthesis.
Keywords:carbon dioxide  hydrogenation  dimethyl ether  CuO-ZnO-Al_2O_3 /HZSM-5 catalyst  Cu/Zn ratio
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