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作 者:汤清虎[1] 裴晓燕[1] 魏志伟[1] 王京[1] 王菲菲[1] 魏民[1] 赵培正[1]
机构地区:[1]河南师范大学化学化工学院,绿色化学介质与反应省部共建教育部重点实验室,河南新乡453007
出 处:《中国稀土学报》2013年第2期190-196,共7页Journal of the Chinese Society of Rare Earths
基 金:国家大学生创新性实验计划项目(101047621);河南省高校科技创新人才支持计划(2010HASTIT028)资助
摘 要:采用回流法合成氧化锰八面体分子筛(OMS-2),并采用浸渍法负载Ce制备Ce-OMS-2催化剂,以分子氧为氧化剂考察了催化剂对苯甲醇液相氧化制苯甲醛的活性。当Ce含量为30%(质量分数)时,Ce-OMS-2催化剂的活性最高。100℃下反应1 h时,苯甲醇转化率为50.3%,催化剂的质量比活性达10.1 mmol.(g.h)-1。采用X射线衍射(XRD)、透射电镜(TEM)、X射线光电子能谱(XPS)、红外光谱(FT-IR)、程序升温还原(H2-TPR)对催化剂进行了表征。结果表明:所制备的催化剂具有结晶良好的八面体结构,当Ce含量小于30%时,Ce以高分散形式存在,但当Ce含量大于30%时,将出现聚集态CeO2结晶;高分散CeO2促进了OMS-2中MnOx的还原,改善了活性中心的电子传递,从而显著提高了催化剂活性。The manganese oxide octahedral molecular sieves (OMS2) were synthesized by a reflux method. CeOMS2 catalysts with different Ce loadings were prepared by the impregnation method. The catalytic performance of CeOMS2 for the oxidation of benzyl alcohol to benzaldehyde with molecular oxygen in liq uidphase was studied. The catalytic activity of Ce OMS2 with a Celoading of 30% (mass fraction) was the highest, and the benzyl alcohol conversion was 50. 3% with the mass specific activity of 10. 1 mmol.(g·h)I at 100 ℃ in 1 h. The XRD, TEM,XPS, FTIR, and H2TPR were used to characterize CeOMS2 catalysts. The synthesized catalysts pos sessed good crystalline structure of octahedral molecu lar sieve. The highly dispersed CeO2 species could be obtained with a Celoading up to 30%, whereas large amount of Ce resulted in aggregated CeO2 crystalline clusters. The highly dispersed CeO2 species on OMS2 played an important role in catalytic performance of the CeOMS2 catalyst, promoting the reduction of MnOx, favoring the electrical transfer of active sites, and thus remarkably enhancing the catalytic activity.
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