부산대학교 도서관

Ordered CrO nanorods (CrO-R) and CrO nanoparticles (CrO-P) were prepared by a hard template method with SBA-15 and a deposition-precipitation method, respectively. These catalysts were tested for the fluorination of 2-chloro-1,1,1-trifluoroethane (HCFC-133a) to synthesize 1,1,1,2-tetrafluoroethane (HFC-134a). It was found that both catalysts were very selective, with a HFC-134a selectivity of 98 %. However, the CrO-R catalyst had an area specific reaction rate of 0.012 μmol m s at 320 °C, which was much higher than that on the CrO-P (0.005 μmol m s). The enhanced activity of the CrO-R was attributed to its higher content of Cr(VI) species compared to that in the CrO-P, which was evidenced by the hydrogen temperature-programmed reduction and X-ray photoelectron spectroscopy results. Besides, the CrO-R catalyst had a higher surface acid density (0.076 mmol m) than the CrO-P (0.068 mmol m), which could be another reason for its better performance. [ABSTRACT FROM AUTHOR]