【作者】 蔡丽莉；

【导师】 张志刚；

【作者基本信息】 华东理工大学 ， 工业催化， 2011， 硕士

【摘要】 本文以Pd-Fe催化剂为主要研究对象,1采用共沉淀法,优化制备条件后制得的Pd/Fe(OH)x催化剂；2采用共沉淀法,掺杂其他过渡金属,制得Pd-M/Fe(OH)x催化剂；3采用浸渍法和溶胶-凝胶法制备Pd-Fe-Ox/Al2O3催化剂。考察结果显示,载体Fe(OH)x的形成非常重要,它对Pd/Fe(OH)x-R催化剂活性的影响最大。利用共沉淀法掺杂Ce, La, Cu, Mn, Sn,形成Pd-M/Fe(OH)x-R催化剂(M=Ce, La, Cu, Mn, Sn),研究考察了稀土元素Ce,La和过渡元素Cu, Mn, Sn等掺杂之后对CO催化活性的影响。考察结果显示,Ce掺杂后性能最佳。本文使用共浸渍法和柠檬酸溶胶-凝胶法制备的Pd-Fe-Ox/Al2O3催化剂活性差异最大。为此对这两种催化剂进行BET,XRD,H2-TPR, XPS表征,发现制备方法会影响PdO颗粒尺寸,以及Pd与Fe之间的相互作用力,和Pd2+/Pd0不同比值,从而导致了CO催化氧化的不同活性。同时,我们还对sol-gel-Pd-Fe-Ox/Al2O3-R催化剂进行了不同Pd-Fe比的考察。从考察结果中发现,催化剂活性随着Fe含量的增加而增加,但是当Fe含量达到15%时,活性开始下降。通过对这一系列不同Pd-Fe比的sol-gel-Pd-Fe-Ox/Al2O3-R催化剂进行BET,XRD, H2-TPR表征后发现,Fe含量的增加,加强了Pd-Fe之间的相互作用力,增加了PdO的氧化性。更多还原

【Abstract】 The Pd-M/Fe(OH)x (M=Ce, La, Cu, Mn, Sn) catalysts were prepared by co-precipitation menthod. The results reveal that the catalytic activity of Pd/Fe(OH)x catalyst is the best. Then Pd-Fe-Ox/Al2O3 catalysts were prepared by co-impregnation (co-Pd-Fe-Ox/Al2O3) and sol-gel method (sol-gel-Pd-Fe-Ox/Al2O3), and characterized by BET, X-ray diffraction (XRD), H2-temperature programmed reduction (H2-TPR), and X-ray photoelectron spectroscopy (XPS). The temperatures of 100% conversion for CO oxidation (T100) over reduced co-Pd-Fe-Ox/Al2O3 and sol-gel-Pd-Fe-Ox/Al2O3 are 90 and 25℃for 1% CO/Air, respectively. XRD results indicate that the sol-gel method is favorable for the more highly dispersion of PdO particles compared with simultaneous wet impregnation method. H2-TPR results suggest that the interaction between Pd and Fe is existent over both sol-gel-Pd-Fe-Ox/Al2O3 and co-Pd-Fe-Ox/Al2O3 catalysts, and the interaction over former catalyst is stronger than that over latter catalyst. The XPS results show that the surface Pd species are the mixture of oxide and metal state for reduced sol-gel-Pd-Fe-Ox/Al2O3 and reduced co-Pd-Fe-Ox/Al2O3 catalysts, leading to the high activity for CO oxidation. Furthermore, the different Pd2+/Pd0 value accounts for the different activity of reduced and reduced co-Pd-Fe-Ox/Al2O3 catalysts.The influce of Fe content over sol-gel-Pd-Fe-Ox/Al2O3 catalysts for CO oxidation was also investigated in this paper. T100 over sol-gel-Pd-Fe-Ox/Al2O3 (Pd wt.%=1%, Fe wt.%=13.86%)catalyst is 25℃for 1% CO/Air. The characterized results indicate the introducing Fe would increase the interaction between Pd and Fe, and stabilize PdO species.更多还原