화학공학소재연구정보센터
Applied Surface Science, Vol.362, 297-303, 2016
Hydrotalcite-derived cobalt-aluminum mixed oxide catalysts for toluene combustion
Hydrotalcite-like compounds (HTlcs) containing cobalt and aluminum (intended Co/Al molar ratio = 3.0) were coprecipitated at 30, 50 and 70 degrees C. Their crystallinity, which was confirmed by powder X-ray diffraction, increased with the precipitation temperature. Furthermore, HTlcs with various cobalt contents were prepared at 70 degrees C. Thermogravimetric analysis showed that HTlcs were transformed into stable oxides at 550 degrees C. The decrease in the crystallite size of the formed spinels with the increase in the precipitation temperature was observed. Low temperature sorption of nitrogen revealed meso-macroporous nature of the oxides with extended interparticle porosity. Aluminum segregated on the samples surface, which contained various amounts of lattice and adsorbed/electrophilic oxygen as detected by X-ray electron spectroscopy. The high ratio of lattice to adsorbed/electrophilic oxygen found for the sample with Co/Al = 3:1 caused that it turned out to be the most efficient catalyst in the total oxidation of toluene (50% conversion at 257 degrees C). (C) 2015 Elsevier B.V. All rights reserved.