Supported MoS2 based materials are widely used as heterogeneous catalysts. In this work, we propose a rapid and facile method (ultrasound-induced impregnation assisted by microwave thermal treatment) to synthesize mesoporous silica (SBA-15)-supported, few-layer, ordered and K-promoted MoS2 nanosheets with different K/Mo ratios. The prepared catalysts are characterized by various physical and chemical techniques. Their catalytic performance is evaluated by methyl mercaptan (CH3SH) synthesis from CO/H-2/H2S. The results show that our catalysts exhibit a much higher CO conversion and selectivity to CH3SH than the catalysts prepared using the conventional impregnation and reported in the literature. The good performance arises because of two main factors: MoS2 nanosheets of only 2-4 layers and K promotion. Experimental characterizations and (density functional theory) calculations show that the former is the typical nano-size effect, and the latter stabilizes C-S bonds when activating COS molecules. (C) 2020 Elsevier Inc. All rights reserved.