Promotional effects of samarium on Co_3O_4 spinel for CO and CH_4 oxidation  

作　　者：徐香兰 韩红 刘建军 刘文明 李文龙 王翔 

机构地区：[1]Institute of Applied Chemistry,Department of Chemistry,Nanchang University

出　　处：《Journal of Rare Earths》2014年第2期159-169,共11页稀土学报（英文版）

基　　金：supported by National Natural Science Foundation of China(21263015,21203088);Education Department of Jiangxi Province(GJJ12045)

摘　　要：A series of CO3O4 spinel catalysts modified by Sm were prepared by co-precipitation method and tested for CH4 and CO oxidation. The addition of a small amount of Sm into Co3O4 led to an improvement in the catalytic activity for both reactions. Co0.98Sm0. 02 and Co0.95Sm0.05, the two samples with Co/Sm molar ratio of 0.98/0.02 and 0.95/0.05 in sequence, showed the similar and the highest activity for CH4 oxidation, with CH4 complete conversion at 450 ℃. In contrast, Coo.90Smo l0 was the most active sample for CO oxidation, with CO complete conversion at 120 ℃. The catalysts were characterized by techniques of N2 adsor- tion-desorption with Brunauer-Emmett-Teller technique （N2-BET）, X-ray powder diffraction （XRD）, thermal gravity analy- sis-differential scanning calorimetry （TGA-DSC）, Hz temperature programmed reduction （H2-TPR） and X-ray photoelectron spec- troscopy analysis （XPS）. Compared with pure Co3O4, for CO1-xSmx catalysts with 0.02≤x≤0.10, the addition of a small amount of Sm resulted in the formation of spinel Co3O4 and amorphous SmCoO3, hence increasing the number of Co3＋ and the active surface oxygen species, which was responsible for the improvement of the activity. C00.95Sm0.05 catalyst showed not only high thermal stability and activity but also good reaction durability in the presence of 5% water vapor for CH4 oxidation.A series of CO3O4 spinel catalysts modified by Sm were prepared by co-precipitation method and tested for CH4 and CO oxidation. The addition of a small amount of Sm into Co3O4 led to an improvement in the catalytic activity for both reactions. Co0.98Sm0. 02 and Co0.95Sm0.05, the two samples with Co/Sm molar ratio of 0.98/0.02 and 0.95/0.05 in sequence, showed the similar and the highest activity for CH4 oxidation, with CH4 complete conversion at 450 ℃. In contrast, Coo.90Smo l0 was the most active sample for CO oxidation, with CO complete conversion at 120 ℃. The catalysts were characterized by techniques of N2 adsor- tion-desorption with Brunauer-Emmett-Teller technique （N2-BET）, X-ray powder diffraction （XRD）, thermal gravity analy- sis-differential scanning calorimetry （TGA-DSC）, Hz temperature programmed reduction （H2-TPR） and X-ray photoelectron spec- troscopy analysis （XPS）. Compared with pure Co3O4, for CO1-xSmx catalysts with 0.02≤x≤0.10, the addition of a small amount of Sm resulted in the formation of spinel Co3O4 and amorphous SmCoO3, hence increasing the number of Co3＋ and the active surface oxygen species, which was responsible for the improvement of the activity. C00.95Sm0.05 catalyst showed not only high thermal stability and activity but also good reaction durability in the presence of 5% water vapor for CH4 oxidation.

关 键 词：CO3O4 SmCoO3 CO and CH4 oxidation water vapor effect rare earths 

分 类 号：O643.3[理学—物理化学]