Mesoporous carbons as metal-free catalysts for propane dehydrogenation: Effect of the pore structure and surface property  

介孔碳作为非金属丙烷脱氢催化剂:孔道结构和表面性质的影响（英文）

作　　者：Zhong-Pan Hu Jin-Tao Ren Dandan Yang Zheng Wang Zhong-Yong Yuan 胡忠攀;任金涛;杨丹丹;王政;袁忠勇(南开大学材料科学与工程学院,先进能源材料化学教育部重点实验室,天津300350;宁夏大学化学化工学院,省部共建煤炭高效利用与绿色化工国家重点实验室,宁夏银川750021)

机构地区：[1]Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education),School of Materials Science and Engineering,Nankai University,Tianjin 300350,China [2]State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering,College of Chemistry and Chemical Engineering,Ningxia University,Yinchuan 750021,Ningxia,China

出　　处：《Chinese Journal of Catalysis》2019年第9期1385-1394,共10页催化学报（英文）

基　　金：supported by the National Natural Science Foundation of China(21421001,21573115);the Fundamental Research Funds for the Central Universities(63185015);the Foundation of State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering(2017-K13)~~

摘　　要：Nanocarbon materials have been used as important metal-free catalysts for various reactions including alkane dehydrogenation.However,clarifying the active sites and tuning the nanocarbon structure for direct dehydrogenation have always been significantly challenging owing to the lack of fundamental understanding of the structure and surface properties of carbon materials.Herein,mesoporous carbon materials with different pore ordering and surface properties were synthesized through a soft-templating method with different formaldehyde/resorcinol ratios and carbonization temperatures and used for catalytic dehydrogenation of propane to propylene.The highly ordered mesoporous carbons were found to have higher catalytic activities than disordered and ordered mesoporous carbons,mainly because the highly ordered mesopores favor mass transportation and provide more accessible active sites.Furthermore,mesoporous carbons can provide a large amount of surface active sites owing to their high surface areas,which is favorable for propane dehydrogenation reaction.To control the surface oxygenated functional groups,highly ordered mesoporous carbons were carbonized at different temperatures(600,700,and 800℃).The propylene formation rates exhibit an excellent linear relationship with the number of ketonic C=O groups,suggesting that C=O groups are the most possible active sites.作为一种非金属催化剂,纳米碳材料被广泛应用于各种催化反应.尤其在近几年,纳米碳材料被发现是一种良好的烷烃脱氢催化剂.但是,由于缺乏对碳材料的结构和表面性质方面的基础研究,碳材料在烷烃直接脱氢反应中的活性位点并不明确.另外,由于碳材料本身的复杂结构,精确调控碳材料的微观孔道结构,研究碳材料的结构特性对其烷烃脱氢反应性能的影响仍存在较大难度.本文利用软模板和控制焙烧的方法合成出一系列具有不同孔道有序性和表面性质的介孔碳材料,系统研究了介孔碳孔道有序性和表面含氧官能团种类、含量等因素对介孔碳材料丙烷脱氢性能的影响.XRD,SEM,TEM和氮气吸附结果显示,通过添加F127可将介孔孔道引入到碳材料中;调节间苯二酚和甲醛的比例可以实现介孔碳材料孔道有序性的调控;在保证碳材料孔道有序性的前提下,通过控制焙烧温度可以精确调节碳材料表面的含氧官能团种类和数量.然后,将该系列碳基催化剂进行丙烷脱氢测试.结果发现,介孔的引入可以为丙烷脱氢反应提供大量的活性位点,因而介孔碳比无孔碳具有更加优异的丙烷脱氢活性.对于介孔碳材料,孔道越有序,表面含氧官能团越多的介孔碳材料表现出更加优异的丙烷脱氢性能.因为高度有序的介孔孔道有利于反应物和反应产物的传质,降低催化反应的空间位阻,从而提高催化剂的活性,选择性和稳定性.碳材料表面的含氧官能团被认为是丙烷脱氢的主要活性位点,含氧官能团越多,活性位点越多,因而活性就越好.但是,介孔碳表面含有各种不同的含氧官能团(羧基、羟基和碳基).结合XPS和丙烷脱氢测试结果,将不同温度处理后的有序介孔碳的丙烯生成速率和表面含氧官能团含量进行拟合.结果表明,介孔碳材料表面的羰基含量与其丙烯生成速率之间具有非常好的线性关系,而�

关 键 词：Mesoporous carbons PROPANE DEHYDROGENATION PROPYLENE Metal-free catalysis 

分 类 号：TQ426[化学工程] TQ221.212