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;
(Translated by WANG YX)
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