(2.华东理工大学化工学院化学工程联合国家重点实验室, 上海 200237)
【摘要】采用等体积浸渍法制备MoS2/Si-ZrO2催化剂，并对其CO耐硫甲烷化的催化活性稳定性进行评估。结果表明在2H2∶2CO∶1N2（摩尔比）、反应压力2.5 MPa、反应温度450℃、硫含量0.01%及质量空速6000 ml/(g·h)的反应条件下，100 h后CO转化率下降11%。深入进行氢气程序升温还原（H2-TPR）、X射线光电子能谱（XPS）、拉曼光谱（RS）、等离子体发射光谱（ICP-OES）、高分辨透射电子显微镜（HRTEM）、热重分析（TGA）以及元素分析等表征后，发现反应后催化剂表面无明显积炭，但出现了明显的团聚现象。而催化剂失活的根本原因是硫流失的发生，导致具有催化活性的桥键S22-物种转变为S2-物种2和-H2S。
【基金资助】 国家自然科学基金项目(U1203293,21776091,21808062); 中央高校基本科研业务费专项资金(22A1817025); 上海学科首席科学家项目(10Xd1401500); 中国博士后科学基金项目(2017M611474);
Deactivation behaviors of MoS2/Si-ZrO2 catalyst during sulfur-resistant CO methanation
(2.State Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai, China 200237)
【Abstract】The MoS2/Si-ZrO2 catalyst was prepared by an equal volume impregnation method, and the catalytic activity stability of the catalyst for CO sulfur-resistant CO methanation was evaluated. The CO conversion of the MoS2/Si-ZrO2 catalyst decreased by 11% under the following conditions: molar ratio of feed gas composition was 2H2:2CO:1N2; concentration of H2S was 0.01%; weight hourly space velocity was 6 000 mL/(g·h); reaction temperature was 450 °C and reaction pressure was 2.5 MPa. The catalysts were further characterized by hydrogen temperature-programmed reduction (H2-TPR), X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy (RS), inductively coupled plasma-optical emission spectroscopy (ICP-OES), thermogravimetric analysis (TGA) and elemental analysis. The results demonstrated that little carbon deposited on the surface of spent catalyst, which did not cause catalyst deactivation. The minor cause was that MoS2 slabs grew longer and stacked in more layers after long-term reaction and then covered the active sites. The root deactivation cause was attributed to that parts of bridging S22− species with catalytic activity converting to less active S2− species and H2S, which resulted in the loss of active sites and sulfur element.
【Keywords】 deactivation; catalyst; stability; natural gas; sulfur-resistant methanation; bridging S22- species; sulfur loss;
【Funds】 National Natural Science Foundation of China (U1203293, 21776091, 21808062); Fundamental Research Funds for the Central Universities of Ministry of Education of China (22A1817025); Program of Shanghai Subject Chief Scientist (10Xd1401500); China Postdoctoral Science Foundation (2017M611474);
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