【摘要】 研究了掺杂钛酸盐催化剂用于乙烷氧化脱氢（ＯＤＨＥ）的催化行为，发现适量的Ｌｉ＋取代Ｔｉ４＋后可明显改善催化剂对乙烯的选择性．催化剂ＣａＴｉ０．９Ｌｉ０．１Ｏ３－δ在８５０℃时乙烷转化率和乙烯选择性分别为８７．８％和７１．７％，乙烯的单程收率为６３．０％；催化剂Ｓｒ０．９Ｃａ０．１Ｔｉ０．９Ｌｉ０．１Ｏ３－δ可在极宽的温度范围（７００～８５０℃）内保持很高的乙烯选择性（≥９０％）．Ｏ２－ＴＰＤ－ＭＳ和Ｈ２－ＴＰＲ实验结果表明，Ｌｉ＋取代Ｔｉ４＋后在催化剂晶格中产生非完全还原的氧（Ｏδ－），该氧物种是ＯＤＨＥ反应的活性氧种，直接与催化剂的乙烯选择性相关．ＯＤＨＥ反应机理与甲烷氧化机理具有某些相似性．反应条件考察结果表明，低空速有利于乙烷的低温转化，高空速可抑制气相中非催化反应的进行，有利于乙烯的选择性，尤其是高温下乙烯的选择性．更多还原

【Abstract】 The oxidative dehydrogenation of ethane (ODHE) over various Li doped MTiO 3 (M=Ca, Sr) catalysts has been examined in the temperature range of 700-850℃. 87 8% for C 2H 6 conversion, 71 7% for C 2H 4 selectivity and 63 0% for C 2H 4 yield can be obtained over catalyst CaTi 0.9 Li 0.1 O 3- δ at 850℃. The substitution of Sr for Ca in CaTi 0.9 Li 0.1 O 3- δ can maintain a high selectivity (≥90%) for C 2H 4 in a very wide range (700￣850℃). A much better improvement in C 2H 4 selectivity can be observed by substituting of Li + for Ti 4+ in MTiO 3. By means of O 2 TPD MS and H 2 TPR, the effect of Li + doping can be explained by the increment of oxygen vacancy and non fully reduced oxygen species. In the reactor employed in this study, the homogeneous reactions are inhibited by increasing the space velocity.更多还原