On the morphology of MoS2 slabs on MoS2/Al2O3 catalysts: the influence of Mo loading

Abstract

Two-dimensional MoS₂ is an important material with diverse catalytic applications. The edge sites exposed by MoS₂ are of great importance to its catalytic performance since the catalytic reactions generally occur on the edge sites rather than on the basal planes. In this work, low temperature (100 K) CO adsorption followed by IR spectroscopy (IR/CO) was used to in situ probe the edge sites of the MoS₂ phase on MoS₂/Al₂O₃ catalysts. It is found that the morphology of the MoS₂ phase on an Al₂O₃ support is a truncated triangle exposing mainly Mo-terminated edges (M-edge). However, the proportion of sulfur-terminated edges (S-edge) increases with increasing the Mo loading, resulting in a more heavily truncated triangle morphology of MoS₂. The change of MoS₂ morphology with Mo loading can be explained by the modification of MoS₂–Al₂O₃ interactions, indicating the importance of phase-support interactions in supported MoS₂ catalysts.