Effect of potassium addition method on MoS2 performance for the syngas to alcohol reaction

Molybdenum disulfide promoted with alkali metals is one of the most studied catalysts for the conversion of synthesis gas to alcohols. In this work, MoS2 was promoted by adding potassium precursors by physical mixing (PM) and incipient wetness impregnation (IWI) and tested in a small scale reactor. The catalysts prepared by impregnation showed poorer performance compared to the sample prepared by physical mixing of K2CO3 and MoS2. The catalysts were characterized by means of X-ray diffraction, TGA-MS, SEM-EDS, TEM and XPS. The characterization results obtained by SEM-EDS and XRD analyses do not show major differences between the catalysts studied here. In contrast, the TGA results indicated that physical mixing leads to catalysts that lose sulfur at temperatures above 330 degrees C and TEM images showed that randomly oriented small MoS2 crystallites are obtained from PM preparation while IWI preparation gave long MoS2 crystallites. (C) 2013 Elsevier B.V. All rights reserved.