Basicity of Ba-La-O-(F) catalysts and their catalytic performances for theOCM reaction

The structure and surface basicity of a series of lanthanum based catalysts (La2O3, BaO/La2O3, BaF2/La2O3, LaOF, BaF2/LaOF) were characterized by XRD, CO2-TPD and high temperature in situ FTIR spectroscopy of CO2 adsorption. Both the results of CO2-TPD and in situ FTIR spectra of CO2 adsorption indi cate that the basicity of the catalysts decreases in the sequence BaO/La2O3 >La2O3>BaF2/ La2O3 > BaF2/LaOF > LaOF. The experiments of catalytic perform ance evaluation of the catalysts performed at 800 degrees C under the condi tions of V(CH4)/V(O-2) = 4 and GHSV = 15 000 h(-1) indicate that the BaF2 m odified La2O3 and LaOF demonstrate a better OCM performance compared to the corresponding La2O3 and LaOF. These observations suggest that the surface basicity is not always a requisite attribution for a good OCM catalyst.