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Ir/ γ Al 2O 3 catalyst for hydrazine decomposition has been investigated by using XPS, SEM, H 2 TPD and H 2 isothermal adsorption. The results show that the iridium species enrich on the surface of the catalyst in more than one state, and that the metallic iridium is the active sites for the reaction. The iridium species were sintered seriously during the reaction, and the amount of H 2 adsorption on used sample was only a quarter of that on fresh sample. The concentration of Cl - species on the surface decreased quickly at the initial period of the reaction process and stayed at a certain low value. Obvious breakup of the surface structure of the used sample was found. In all, the sintering of metallic iridium and the damage of alumina surface structure are the reasons for deactivation of the catalyst, while the Cl - concentration has little effect on the reaction performance. 相似文献
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虎眼万年青皂苷OSW-1来源于百合科植物虎眼万年青, 是一种具有良好抗肿瘤活性的皂苷成分. 其类似物23-Oxa-OSW-1具有OSW-1一样潜在的活性, 对恶性肿瘤细胞具有很强的抑制作用, IC50为0.052~0.4 μmol8226;L-1. 但OSW-1的生物靶标还没有报道. 利用一维和二维 1H NMR技术首次发现23-Oxa-OSW-1与DNA间有很强的相互作用. NMR数据分析表明23-Oxa-OSW-1中木糖部分可能参与了与DNA的结合. 相似文献
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超细Cu-ZnO-ZrO2催化剂的制备及其催化CO2加氢合成甲醇的性能 总被引:28,自引:2,他引:26
采用溶胶-凝胶法、共沉淀法和共沸蒸馏法制备了一系列不同粒度范围的超细Cu-ZnO-ZrO2催化剂,并应用BET,XRD,TEM和TPR等物理化学方法对催化剂的结构和物化性质进行了表征,同时考察了催化剂上CO2加氢合成甲醇的反应性能.结果表明,超细Cu-ZnO-ZrO2催化剂具有粒度小、颗粒分布均匀和稳定性好的特点,并发现超细Cu-ZnO-ZrO2催化剂比大颗粒的工业Cu-ZnO-Al2O3催化剂具有更高的催化活性,而且随着催化剂粒度的减小,甲醇合成活性进一步增大.研究还发现,ZrO2具有稳定反应活性中心的作用. 相似文献
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