[中文文摘]采用原位时间分辨红外光谱和原位显微Raman光谱技术对Ir/SiO2 上甲烷部分氧化 (POM)制合成气反应的初级产物和反应条件下催化剂表面物种进行了跟踪考察 ,实验结果表明 ,在H2 预还原的新鲜Ir/SiO2 表面 ,CO是V(CH4)∶V(O2 )∶V(Ar) =2∶1∶45混合气反应的初级产物 ,因而甲烷的直接氧化过程是CO生成的主要途径 ;而在稳态反应条件下 ,CO生成的途径可能主要来自CO2 和H2 O与催化剂表面积碳物种 (CHx)和 /或CH4的反应 .催化剂上生成的积碳可能是导致稳态条件下Ir/SiO2 上POM反应机理不同于H2 预还原的新鲜催化剂的主要原因。[英文文摘]In situ time-resolved FTIR and in situ microprobe Raman spectroscopies were used to follow the primary products as well as the surface and gas phase species formed during the reaction of partial oxidation of methane (POM) to synthesis gas over Ir/SiO 2 catalyst. The results suggested that direct oxidation of CH 4 to CO is the dominant pathway of POM reaction over the freshly reduced Ir/SiO 2 catalyst, while the dominant schemes of CO formation over the catalyst under the steady state reaction condition are probably via the reactions of CO2 and H2O with the deposited carbon species (CHx) and/ or CH4 . The mechanistic difference between the POMto synthesis gas over freshly reduced Ir/ SiO2 catalyst and the catalyst under the steady state reaction may have resulted from the formation of significant amount of deposited carbon species in the latter system.国家重点基础研究发展规划 (No.G1999022408); 国家自然科学基金(No.20021002)资助项目
