Mixed alcohols synthesis from syngas over Cs- and Ni-modified Cu/CeO2 catalysts

• Published in: Fuel (Guildford) Vol. 104; pp. 62 - 69
• Main Authors: Liu, Yanyong, Murata, Kazuhisa, Inaba, Megumu, Takahara, Isao, Okabe, Kiyomi
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Kidlington Elsevier Ltd 01.02.2013; Elsevier
• Subjects: Alcohols; Applied sciences; Carbon monoxide; Catalysis; Catalysts; Conversion; Copper; Cs promoter; Cu/CeO2 catalyst; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fuels; Mixed alcohols; Ni promoter; Syngas; Synthesis; Zinc oxide; Mixed alcohols; Cu/CeO2 catalyst; Ni promoter; Cs promoter; Syngas; Deactivation; Alcohol; Alkali metal; Cu/CeO; Cerium oxide; Synthesis gas; Nickel; Isobutane; Catalyst; Coprecipitation; Methanol
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2010.08.014

Cu/CeO2 (cop) was prepared by a coprecipitation method using NH3·H2O as a precipitant (in order to avoid the residues of alkali metals), followed by a boiling process to eliminate NH3 and decompose [Cu(NH3)4]2+ complex. Because the Cu particles in Cu/CeO2 (cop) were much smaller than those in Cu/CeO2 (imp) (prepared by an impregnation method), Cu/CeO2 (cop) showed a higher activity than that over Cu/CeO2 (imp) for the synthesis of mixed alcohols. Moreover, Cu/CeO2 (cop) showed a higher CO conversion than that over the industrial catalyst Cu/ZnO due to the reducibility of CeO2-based compounds. Although either Cu/ZnO or Cu/CeO2 (cop) produced methanol as a dominant product, the STY of higher alcohols (C2+OH) formed over Cu/CeO2 (cop) was much larger than that over Cu/ZnO because CeO2-based compounds could catalyze the synthesis of isobutane from syngas (isosynthesis). When Cs was introduced into the Cu/CeO2 (cop) catalyst, the mass ratio of C2+OH to MeOH in the products greatly increased from 0.13 to 0.71 but the CO conversion decreased slightly. Both the CO conversion and the selectivity for higher alcohols over CsCu/CeO2 (cop) were higher than those over CsCu/ZnO. By introducing Ni (an F–T element) into CsCu/CeO2 (cop), the CO conversion increased from 22.2% to 37.6% and the mass ratio of C2+OH to MeOH in the products increased from 0.71 to 0.85. Therefore, CsNiCu/CeO2 (cop) is an excellent catalyst for the synthesis of mixed alcohols. A slow deactivation was observed over CsNiCu/CeO2 (cop) in the reaction at 573K for 18h. The deactivated catalyst could be regenerated by calcination in air at 723K and followed by reduction in H2 at 573K.