LaFeO3甲烷氧化催化剂的表征及反应性能评价

采用高温熔融法制备出LaFeO3系列催化剂,利用XRD,BET,XPS等分析手段对催化剂样品进行了表征,并通过CH4/O2切换反应考察了催化剂的反应性能.结果表明,纯LaFeO3催化剂具有2个O1s峰,低结合能的氧归属为晶格氧,高结合能的氧归属为吸附氧;负载型的催化剂除了含有晶格氧和吸附氧外,还含有大量与Al2O3结合的表面氧;加入助剂会降低各种结合状态氧的结合能;高温熔融致使催化剂中晶格氧的结合能降低.采用挤条法制备的活性组分质量分数为40％的Al基新鲜LaFeO3催化剂反应性能最佳,其CH4转化率、CO选择性分别为87.9％,97.1％,且产物H2/CO（摩尔比）为2.

Characterization and performance evaluation of LaFeO3 catalyst for methane oxidation

Series of LaFeO3 catalysts were prepared by high temperature fusion method,and X-ray diffraction,BET specific surface area measurement and X-ray photoelectron spectrometry were used to characterize the prepared catalysts.The reaction performance of catalysts were investigated by CH4/O2 switching reaction.The results showed that pure LaFeO3 catalyst had two O1s peaks,the low binding energy oxygen belonged to lattice oxygen,and the high binding energy belonged to adsorption oxygen.The supported catalyst not only contained the lattice oxygen and adsorption oxygen but also contained a large number of surface oxygen whichwere combined to Al2O3.Adding the addition agent reduced the binding energy of oxygen in different binding states,and high temperature melting led to the reduce of binding energy of lattice oxygen.The Al base LaFeO3 fresh catalyst containing 4％ mass fraction of active component,which was prepared by extrusion process,had the best switching reaction performance.When this catalyst was used in CH4 oxidation,the CH4 conversion was 87.9％,the CO selectivity was 97.1％,and the H2/CO （molar ratio） in product was 2.