Enhancing stability of MoS2 catalysts for sulfur-resistant methanation by tuning interlayer interaction

Abstract

A simple one-step hydrothermal synthesis was developed to modulate the stability of MoS2 for catalytic sulfur-resistant methanation. The methanation performance was optimized by tuning hydrothermal time and solution pH value. The catalysts were characterized by Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman spectroscopy and thermogravimetric and derivative thermogravimetric (TG/DTG) analysis. It was found that both extended hydrothermal time and weak acidic solution value was benefit to prepare the MoS2 catalyst with high stacking layers. TG/DTG analysis indicated that no obvious coke deposition occurred in the MoS2 catalysts during methanation reaction. Moreover, density functional theory (DFT) simulation result proved that with the increase of stacking layers, the electron density between Mo atoms and their neighbor S atoms was strengthened and the interlayer interaction was enhanced. Therefore, the MoS2 catalysts with high stacking layers was stable since they were not easily deactivated by sintering or substitution of active S atoms by O atoms during the reaction.