摘要

In the present work we report on the influence of the preparation method on the physicochemical and catalytic properties of La-Ce-Mn-O-catalysts used for methane combustion. Samples were prepared hydrothermally using both conventional ( CH) and dielectric heating (MH). Catalysts were characterized by N(2) adsorption-desorption, X-ray powder diffraction (XRD), temperature-programmed reduction by H(2) (H(2)-TPR) and temperature-programmed desorption-mass spectrometry (TPD-MS). An analysis of XRD and TPR data leads us to conclude that microwave irradiation leads to formation of La(1) (x)Ce(x)MnO(3) epsilon CeO(2) (x epsilon = 0.2), whereas conventional heating leads to CH-LaMnO(3) CeO(2) systems. Catalytic combustion of methane without and with 100 ppmv H(2)S was carried out using a GHSV of 8000 h (1) and oxygen-to-methane ratio of 4. Microwave prepared sample was found to be the best both in terms of sulphur tolerance and percent CH(4) conversion. The superior catalytic performance of the catalyst prepared using dielectric heating was attributed to a well dispersed cerium oxide species strongly interacting with the LaMnO(3) host structure.

  • 出版日期2009-3-10