纳米碳纤维催化丙烷氧化脱氢性能的研究

研究了纳米碳纤维(CNF)新型碳材料催化丙烷氧化脱氢反应的催化性能。通过透射电子显微镜、高分辨率透射电子显微镜、N2吸附及空气气氛中的热重分析方法表征CNF的结构与纯度,考察纯化和氧化活化处理对其催化性能的影响。实验结果表明,化学气相沉积法合成的CNF含有较多金属杂质及表面缺陷位;通过高温热处理能有效去除CNF中的金属杂质,并提高其石墨化程度,催化剂的热稳定性大大提高;A r气氛中1 700℃高温热处理12h,再经过600℃空气氧化活化后得到的CNF为高效的丙烷氧化脱氢催化剂;采用该催化剂,在反应温度550℃、丙烷的转化率51.75%的条件下,丙烯的选择性达32.46%;对于该催化剂,提高反应温度和氧烷比可增加丙烯的收率。

Catalytic Performances of Carbon Nanofiber in Oxidative Dehydrogenation of Propane

Carbon nanofiber(CNF),a kind of new carbon material,synthesized by catalytic vapor deposition method was used as catalyst for oxidative dehydrogenation of propane(ODP).Structures and purities of the CNF were characterized by means of transmission electron microscope(TEM),high resolution transmission electron microscope(HRTEM),N_2 adsorption and thermogravimetry(TG)in air.A large amount of defect sites and metal impurities existed in CNF which could be effectively removed by high temperature treatment.As a result, thermal stability of CNF increased.CNF after heat treatment in Ar at 1 700℃ for 12h and successive activation in air at 600℃ became an effective catalyst for ODP.At 550℃,propene selectivity could mount to (32.46%) when propane conversion was (51.75%.) Higher reaction temperature and higher n(oxygen) ∶(n(propane))were favorable to higher propene yield.