학술논문
稀土掺杂改性对Cu/ZnAl水滑石衍生催化剂甲醇水蒸气重整制氢性能的影响 / Effect of rare-earth element modification on the performance of Cu/ZnAl catalysts derived from hydrotalcite precursor in methanol steam reforming
Document Type
Academic Journal
Author
杨淑倩; 贺建平; 张娜; 隋晓伟; 张磊; 杨占旭; YANG Shu-qian; HE Jian-ping; ZHANG Na; SUI Xiao-wei; ZHANG Lei; YANG Zhan-xu
Source
燃料化学学报 / Journal of Fuel Chemistry and Technology. 46(2):179-188
Subject
Language
Chinese
ISSN
0253-2409
Abstract
采用原位合成法在γ-Al2 O3表面合成了锌铝水滑石,再通过顺次浸渍法制备了一系列掺杂稀土改性的M(M=Y、La、Ce、Sm、Gd)/Cu/ZnAl催化材料,并将其应用于甲醇水蒸气重整制氢反应.探讨了稀土掺杂改性对Cu/ZnAl催化剂催化性能的影响,并采用XRD、SEM-EDS、BET、H2-TPR、XPS和N2O滴定等手段对催化剂进行了表征.结果表明,催化剂的活性与Cu比表面积和催化剂的还原性质密切相关,Cu比表面积越大,还原温度越低,催化活性越高.稀土Ce、Sm、Gd的引入能改善活性组分Cu的分散度、Cu比表面积以及催化剂的还原性质,进而提高催化剂的催化活性.其中,Ce/Cu/ZnAl催化剂表现出最佳的催化活性,在反应温度为250℃时,甲醇转化率达到100％,CO含量为0.39％,相比Cu/ZnAl催化剂,甲醇转化率提高了近40％.
Zn-Al layered double hydroxides (ZnAl-LDHs) were prepared on γ-Al2O3 by an in-situ synthesis method;with ZnAl-LDHs as the supports,a series of rare-earth element M (M =Y,La,Ce,Sm and Gd) doped M/Cu/ZnAl catalysts were then obtained through sequential wet impregnation method and used in the methanol steam reforming to produce hydrogen.The M/Cu/ZnAl catalysts were characterized by XRD,SEM-EDS,N2 sorption,H2-TPR,XPS and N2O titration and the effect of rare-earth metal doping on their catalytic performance in the methanol steam reforming was then investigated.The results showed that the activity of Cu/ZnAl catalyst is closely related to the copper surface area and the reducibility;larger copper surface area and lower reduction temperature lead to a higher catalytic activity in methanol steam reforming.The addition of rareearth elements including Ce,Sm and Gd can improve the copper dispersion,surface copper area and the catalyst reducibility,which is helpful to enhance the activity of M/Cu/ZnAl catalysts.Especially,the Ce/Cu/ZnAl catalyst exhibits the highest activity;over it,the methanol conversion is 100％ (about 40％ higher than that over the Cu/ZnAl catalyst) and the CO concentration in the product is only 0.39 ％,for the methanol steam reforming at 250 ℃.
Zn-Al layered double hydroxides (ZnAl-LDHs) were prepared on γ-Al2O3 by an in-situ synthesis method;with ZnAl-LDHs as the supports,a series of rare-earth element M (M =Y,La,Ce,Sm and Gd) doped M/Cu/ZnAl catalysts were then obtained through sequential wet impregnation method and used in the methanol steam reforming to produce hydrogen.The M/Cu/ZnAl catalysts were characterized by XRD,SEM-EDS,N2 sorption,H2-TPR,XPS and N2O titration and the effect of rare-earth metal doping on their catalytic performance in the methanol steam reforming was then investigated.The results showed that the activity of Cu/ZnAl catalyst is closely related to the copper surface area and the reducibility;larger copper surface area and lower reduction temperature lead to a higher catalytic activity in methanol steam reforming.The addition of rareearth elements including Ce,Sm and Gd can improve the copper dispersion,surface copper area and the catalyst reducibility,which is helpful to enhance the activity of M/Cu/ZnAl catalysts.Especially,the Ce/Cu/ZnAl catalyst exhibits the highest activity;over it,the methanol conversion is 100％ (about 40％ higher than that over the Cu/ZnAl catalyst) and the CO concentration in the product is only 0.39 ％,for the methanol steam reforming at 250 ℃.