Deactivation behaviors of MoS2/Si-ZrO2 catalyst during sulfur-resistant CO methanation

The MoS2/Si-ZrO2 catalyst was prepared by an equal volume impregnation method, and the catalytic activity stability of CO for sulfur-tolerant methanation was evaluated. The CO conversion of the MoS2/Si-ZrO2 catalyst decreased by 11% under the following condition: molar ratio of feed gas composition was 2H2:2CO:1N2; concentration of H2S was 0.01%; weight hourly space velocity was 6000 ml/(g•h); reaction temperature was 450℃ and reaction pressure was 2.5 MPa. The catalysts were further characterized by hydrogen temperature programmed reduction (H2-TPR), X-rays photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM), Raman spectra (RS), inductively coupled plasma emission spectra (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 more layers after long-term reaction and then covered the active sites. The root deactivation cause was attributed to parts of catalytic active bridging S22- species converting to less active S2- species and H2S, which resulted in the loss of active sites and sulfur element. © All Right Reserved.