Alkali-Promoted Trimetallic Co-Rh-Mo Sulfide Catalysts for Higher Alcohols Synthesis from Synthesis Gas: Comparison of MWCNT and Activated Carbon Supports

作者：Surisetty Venkateswara Rao; Dalai Ajay Kumar^*; Kozinski Janusz

来源：Industrial & Engineering Chemistry Research, 2010, 49(15): 6956-6963.

DOI：10.1021/ie100427j

Multiwalled carbon nanotubes (MWCNTs) and activated carbon were used as supports for the Co (4.5 and 6 wt %) promoted K (9 wt %) modified Rh-Mo catalysts (1.5 wt % Rh and 15 wt % Mo). The catalysts were extensively characterized in both oxide and sulfide phases. A drastic fall in surface area over the activated carbon-supported catalysts was observed after impregnating with metal species. Diffraction peaks were observed in the X-ray diffraction (XRD) patterns of the sulfided alkali-modified trimetallic catalysts, due to the characteristic reflections of the K Mo S mixed phase. H(2)-temperature programmed reduction (TPR) profiles showed that the reduction behavior of metal species was improved with the addition of Co. The activated carbon-supported trimetallic catalysts showed less activity and selectivity compared to the MWCNT-supported catalyst, and metal dispersions were higher on the MWCNT-supported catalysts. The MWCNT-supported, alkali-promoted trimetallic catalyst with 4.5 wt % Co showed the highest total alcohols yield of 0.244 g/(g cat h), ethanol selectivity of 20.1%, and higher alcohols selectivity of 31.4% at 320 degrees C and 8.28 MPa using a gas hourly space velocity (GHSV) of 3.6 m(3) (STP)/(kg catalyst h). A maximum total alcohol yield of 0.261 g/(g cat h) and a selectivity of 42.9% were obtained on the 4.5 wt % Co-Rh-Mo-K/MWCNT catalyst, at a temperature of 330 degrees C. The total alcohol yield increased from 0.163 to 0.256 g/(g cat h) with increased pressure from 5.52 MPa (800 psig) to 9.65 MPa (1400 psig) over the 4.5 wt % Co-Rh-Mo-K/MWCNT catalyst.

• 出版日期2010-8-4