厦门大学学报（自然科学版）2001，Vol.40Issue(2)：349-359,11.
甲烷氧化偶联催化剂和部分氧化反应机理的原位及非原位谱学表征
In situ and ex situ Spectroscopic Characterization on the Catalysts for Methane Oxidative Coupling and on the Mechanism of Methane Partial Oxidation
摘要
Abstract
Active oxygen specie and surface acid/base properties of fluoride-containing rare earth-based catalysts for methane oxidative coupling (OCM) reaction were studied using in situ IR and in situ microprobe Raman spectroscopies, XPS, UV spectra of pyridine (Py) adsorption, Py- and CO2-TPD. O-2 species was detected over O2 and/or CH4/O2 pretreated SrF2/La2Oa, SrF2/Nd2O3, LaOF, BaF2/LaOF and BaF2/CeO2 catalysts at OCM reaction temperature, and the reactions between O-2 species and CH4 to form C2H4 and corresponding side-products of OCM reaction such as CO2 and surface carbonate were observed over SrF2/La2O3, SrF2/Nd2O3, LaOF, BaF2/LaOF catalysts. These results, for the first time, provide direct spectroscopic evidences which suggest that O-2 is the active oxygen species for OCM reaction over the corresponding catalysts. It is also found that the surface basicity is not always a requisite attribute for a good OCM catalyst. The results of in situ time-resolved FTIR and in situ microprobe Raman spectroscopic characterizations on the partial oxidation of methane (POM) reaction indicate that direct oxidation of CH4 to synthesis gas is the main pathway of POM reaction over Rh/SiO2 catalyst, while the combustion-reforming scheme is the dominant pathway of synthesis gas formation over Ru/γAl2Oa and Ru/SiO2 catalysts. The significant difference in the reaction schemes of POM reaction over SiO2 and γ-A12O3 supported Rh and Ru catalysts may be related to the difference in surface concentration of oxygen species (O2-) over the catalysts under the reaction conditions mainly due to the difference in oxygen affinity of the two metals关键词
甲烷/氧化偶联/部分氧化/合成气/氧物种/酸碱性/反应机理/原位(时间分辨)红外光谱/原位显微Raman光谱/含氟稀土基催化剂/Rh/SiO2/Ru/γ-Al2O3/Ru/SiO2分类
化学化工引用本文复制引用
翁维正,龙瑞强,陈明树,万惠霖..甲烷氧化偶联催化剂和部分氧化反应机理的原位及非原位谱学表征[J].厦门大学学报（自然科学版）,2001,40(2):349-359,11.
