The catalytic decomposition of CF₄ over Ce/Al₂O ₃ modified by a cerium sulfate precursor

The effect of alumina-based catalysts modified by cerium sulfate on the decomposition CF₄ at reaction temperatures below 700 °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.