Effect of Lanthanum Promotion on the Unsupported Mo–Co–K Sulfide Catalysts for Synthesis of Mixed Alcohols from Syngas

Abstract

The unsupported Mo-Co-K sulfide catalysts promoted by La were prepared through ultrasonic technology in non-aqueous medium and its performances for the synthesis of mixed alcohols from syngas were also investigated. The results showed that the catalysts promoted by La exhibited higher CO conversion and selectivity to ethanol than the unsupported Mo-Co-K sulfide catalyst without addition of La did under identical reaction conditions. The catalysts were characterized by N 2 adsorption/ desorption, X-ray diffraction (XRD), Scanning electron microscope (SEM), Transmission electron microscope (TEM), Raman, and X-ray photoelectron spectroscopy (XPS).

Effects of Adding Cobalt and Potassium to MoS₂-based Catalysts on Mixed Alcohol Synthesis

“…Our previous study investigated the effects of acidity on the supports or catalysts in mixed alcohol synthesis 6) . In other reports, the selectivities for C2 alcohols with unsupported and activated carbon-supported K _ Co _ MoS2 were 71-72 % 20), 21) and 84-90 % (CO2 excluded) 22) 25) , respectively. CO conversion with either unsupported or supported catalyst was 13-15 %.…”

Mixed MgAl Oxide Supported Potassium Promoted Molybdenum Sulfide as a Selective Catalyst for Higher Alcohol Synthesis from Syngas

“…These catalysts include modified Fischer-Tropsch or methanol synthesis catalysts, which are typically adapted for alcohol synthesis by adding promoters such as alkali or other transition metals. Another class of catalysts developed in the late 1980s for these reactions is based on alkali promoted molybdenum sulfide [6][7][8][9] which is commonly combined with cobalt [10][11][12][13]. While molybdenum sulfide based catalysts facilitate reactions that are largely selective for alcohols, their catalytic activity relative to noble metal catalysts, such as those based on Rh, is lower [14][15][16][17][18][19].…”

Light Olefin Synthesis from Syngas over Sulfide–Zeolite Composite Catalyst

“…XRD patterns of MoS 2 – x K catalysts are shown in Figure . Pure MoS 2 retained broad diffraction peaks of crystalline hexagonal MoS 2 at 2θ = 14.4, 33.3, 39.7, and 58.7° . With the introduction of potassium into the MoS 2 , the peaks ascribed to MoS 2 weakened.…”

“…Pure MoS 2 retained broad diffraction peaks of crystalline hexagonal MoS 2 at 2θ = 14.4, 33.3, 39.7, and 58.7°. 19 With the introduction of potassium into the MoS 2 , the peaks ascribed to MoS 2 weakened. K 2 CO 3 phase could not be observed in the XRD pattern of MoS 2 −0.2K, indicating that K 2 CO 3 phase either was highly dispersed on the MoS 2 surface or was in the presence of an amorphous form.…”

“…The unsupported MoS 2 -based catalysts were prepared by the coprecipitation method. 19 Briefly, aqueous solutions of acetic acid (CH 3 COOH) and ammonium tetrathiomolybdate ((NH 4 ) 2 MoS 4 ) were simultaneously added to a container under continuous stirring. Hydrogen ion reacted immediately with the thiomolybdate and a black suspension was formed.…”