摘要
研究了Ｆｅ－Ｐ－Ｏ催化剂对甲烷氧化偶联（ＯＣＭ）的低温催化活性，考察了催化剂组分的优化，最适宜的反应温区，反应过程参数，助催化剂组分，催化剂的晶型结构和活性相以及Ｆ：元素键合状态的ＸＰＳ谱．确定了８％ＬｉＮＯ３－０．８Ｆｅ／Ｐ催化剂在６５０℃，ＣＨ４：Ｏ２：Ａｒ＝２：１：２及ＧＨＳＶ＝３０００ｈ－１条件下，可获得甲烷转化率为１１．９０％和Ｃ２烃选择性为６９．８１％的结果．添加ＬｉＮＯ３为助催成分，可有效改善催化剂表面酸活性中心的分布，防止ＯＣＭ中深度氧化和表面积炭，提高Ｃ２和Ｃ２烃选择性．该催化剂为可变价型，是六方形和料方形两种晶型结构的复合磷酸铁，活性相为斜方形ＦｅＰＯ４物相．
The main aim of this research is the development of a Fe-P-O catalyst for oxidative coupling of methane(OCM) at lower temperature(600-700℃ ).The optimum composition of the catalyst, the optimumtemperature and process variables of the reaction were investigated.The function of lithium as a kind of alkali promoter is considered to reduce the surface acidity and depress the nonselective oxidation. On 8%LiNO3-0. 8 Fe/P catalyst, a CH. conversion of 11.90% with C, selectivity of 69. 81 % and C, yield of 8. 31 % is obtained under the conditions ofT=650℃, CH4: O2: Ar(vol ratio) = 2:1:2 and GHSV=3000 h-1.It is shown that the Fe-P-O catalyst is reducible. The XRD spectra denote that the bulk phase in the fresh catalyst is hexagonal ferric phosphate, but a new phase appeared after reaction and was identified as trimetric. The valence of iron in used catalyst was characterized by XPS.
关键词
甲烷
氧化偶联
铁
磷
氧
methane, oxidative coupling, ferric phosphate,characterization
