焙烧温度对Ni/MgO催化剂结构及其在甲苯二氧化碳重整反应中催化性能的影响(英文)  

Effect of Calcination Temperature on Characteristics and Performance of Ni/MgO Catalyst for CO_2 Reforming of Toluene

作　　者：孔猛[1] 杨琦[1] 卢雯[1] 范浙永[1] 费金华[1] 郑小明[1] Thomas D.WHEELOCK 

机构地区：[1]浙江大学催化研究所,浙江省应用化学重点实验室,浙江杭州310028 [2]艾奥瓦州立大学化学与生物工程系,美国埃姆斯50011

出　　处：《催化学报》2012年第9期1508-1516,共9页

基　　金：国家高技术研究发展计划(863计划,2007AA05Z415);浙江省自然科学基金(Y407113)~~

摘　　要：考察了焙烧温度对 Ni/MgO 催化剂结构及其在甲苯二氧化碳重整反应中催化性能的影响. 由于 NiO-MgO 固溶体的形成,样品的 X 射线衍射谱中没有出现明显的 NiO 衍射峰, 而在拉曼光谱中出现明显的散射信号. X 射线光电子能谱、氢气程序升温还原和 H2脉冲吸附结果表明, 高温焙烧过程中 Ni 向催化剂体相扩散, 与 MgO 发生强互相互作用, 使得 Ni 物种难以还原,但部分位于催化剂表面的 Ni 物种能够还原; 高温焙烧后催化剂表面活性 Ni 物种明显减少, 致使催化剂重整活性降低. 重整反应后, 催化剂表面存在少量多核芳烃类积炭, 这很可能是高温焙烧催化剂稳定性差的原因.A Ni/MgO catalyst for CO2 reforming of toluene was prepared by impregnating MgO with Ni（NO3）2. During calcination, some of the NiO diffused into the MgO and formed a solid solution structure of NiO-MgO, which was analyzed by Raman spectroscopy. In the tem- perature-programmed reduction with hydrogen analysis, only a small part of the Ni species in the outermost layer was reduced to metallic Ni at 700 ℃. The calcination temperature played a key role in determining the subsequent catalytic activity of Ni/MgO, consequently the cata- lyst calcined at 600℃ had the highest activity. This catalyst also had the highest surface concentration of reduced Ni, which probably ac- counted for its high activity. During the reforming tests, a small amount of coke was deposited on Ni/MgO catalyst. Polyaromatic compounds were observed by Raman spectroscopy. The coke was probably responsible for the activity loss of Ni/MgO.

关 键 词：焦油 二氧化碳 重整 镍 氧化镁 负载型催化剂 焙烧温度 拉曼光谱 

分 类 号：O643.32[理学—物理化学]