【摘要】 用尿素均匀沉淀法制备了不同含量锆促进的纳米氧化镍催化剂 ,并考察了其对乙烷氧化脱氢制乙烯的催化性能 .结果表明 ,纯纳米氧化镍在优化条件下的最高乙烯收率为 2 1 7% ;而锆促进的纳米氧化镍催化剂对乙烯选择性和高温抗乙烷裂解性能都有明显改善 .15 %ZrO2 NiO表现出最佳的催化性能 ,在 4 10℃下 ,乙烷转化率为 6 1 5 % ,乙烯选择性为 6 8 6 % ,乙烯收率为 4 2 2 % ;该催化剂在 4 2 0℃经 36h反应 ,乙烯收率仅下降约 4 % ,粒子没有发生明显的团聚 ,表现出较好的稳定性 .XRD结果表明 ,锆促进的纳米氧化镍粒子较纯纳米氧化镍粒子小 ,平均粒径为 5～ 7nm ;助剂锆以无定形的ZrO2 形式存在 .O2 TPD MS结果表明 ,锆的加入提高了催化剂中较高温度下脱附的氧物种量 ,降低了较低温度下脱附的氧物种量 .H2 TPR结果显示 ,锆促进的纳米氧化镍催化剂较纯纳米氧化镍难以完全还原 .更多还原

【Abstract】 The nano ZrO 2 NiO catalyst was prepared by the urea homogeneous precipitation method, and its catalytic performance for oxidative dehydrogenation of ethane to ethylene was studied. The highest C 2H 4 yield over pure nano NiO was 21 7% under the optimized reaction conditions, while ZrO 2 NiO catalyst not only showed higher selectivity for C 2H 4, but also improved the cleavage resistance. Among the samples, 15%ZrO 2 NiO exhibited the best performance in C 2H 6 oxidative dehydrogenation to C 2H 4. The highest yield was 42 2% at 410 ℃ with C 2H 6 conversion of 61 5% and C 2H 4 selectivity of 68 6%. In addition, the catalyst 15%ZrO 2 NiO also showed high stability without agglomeration of nano particles. The nano NiO size decreased after doping with Zr and the average size of ZrO 2 NiO was about 5～7 nm, while ZrO 2 turned to be amorphous. After doping with Zr, the amount of oxygen species desorbed at higher temperature increased, while it decreased at lower temperature. The ZrO 2 NiO catalyst was hard to be reduced than pure nano NiO.更多还原