The catalytic decomposition of CF4 over Ce/Al2O3 modified by a cerium sulfate precursor

Abstract

The effect of alumina-based catalysts modified by cerium sulfate on the decomposition CF4 at reaction temperatures below 700 degrees C was studied. The catalyst characteristics were determined using various techniques, including X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) analysis, ammonia temperature-programmed desorption (NH3-TPD), elemental analysis (EA) and inductively coupled plasma-atomic emission spectroscopy (ICP-AES) to relate the catalytic reactivity with the catalyst properties. The existence of sulfate in alumina-based catalysts provided good catalytic performance due to the increased number of total acidic sites, especially strongly acidic sites, relative to the non-sulfated catalysts. When the catalysts were modified by cerium that could be higher stability in alumina-based catalysts, AlF3 phase that alumina catalyst can be transformed to in CF4 hydrolytic decomposition was not observed on the catalysts. We concluded that the existence of sulfate and cerium in alumina-based catalysts influenced the acid properties, phase composition and specific surface area of the catalysts, which in turn affected the catalyst performance. (c) 2012 Elsevier B.V. All rights reserved.