Plasma assisted preparation of cobalt catalysts by sol-gel method for methane combustion

Novel cobalt catalysts were prepared by sol-gel method, and enhanced by plasma treatment, for methane catalytic combustion. These samples were characterized using X-ray diffraction, X-ray photoelactron spectroscopy, UV-vis spectroscopy, Fourier transform infrared spectroscopy, thermal gravimetrical analysis, N-2 Adsorption-desorption, temperature-programmed reduction and hydrogen-oxygen titration technologies. The XPS characterizations suggested that plasma treatment was favorable for the enrichment of surface cobalt, with a value of surface cobalt from 2.2% to 8.5% in mole. The specific surface area of the glow plasma assised sample (Co-Plas-Solgel-2) increased to 320 m(2)/g comparing with 305 m(2)/g of the conventional sample (Co-Solgel-1). The ignition temperature (T-10%) of Co-Plas-Solgel-2 catalyst was about 50 degrees C lower than that of Co-Solgel-1, and its CH4 conversion was two times higher than that of Co-Solgel-1 during the whole range of catalytic combustion activity test (340-520 degrees C). With a better dispersion and more active sites, the plasma assisted sample exhibited significant enhancement in catalytic performances.