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Title: Effect of the SiO 2 support on the catalytic performance of Ag/ZrO 2/SiO 2 catalysts for the single-bed production of butadiene from ethanol

A ternary Ag/ZrO 2/SiO 2 catalyst system was studied for single-step conversion of ethanol to butadiene by varying the catalyst composition (Ag, Ir, or Pt metal component, Ag/ZrO 2 loading, and choice of SiO 2 support) and operating conditions (space velocity and feed gas composition). Exceptional catalytic performance was achieved over a 1%Ag/4%ZrO 2/SiO 2-SBA-16 catalyst leading to 99% conversion and 71% butadiene selectivity while operating under mild conditions (325°C, 1 atm, and 0.23 h –1). Several classes of silica—silica gels, fumed silicas, mesoporous silicas)—were evaluated as catalyst supports, and SBA-16 was found to be the most promising choice. The SiO 2 support was found to significantly influence both conversion and selectivity. A higher SiO 2 catalyst surface area facilitates increased Ag dispersion which leads to greater conversion due to the accelerated initial ethanol dehydrogenation reaction step. By independently varying Ag and ZrO 2 loading, Ag was found to be the main component that affects ethanol conversion. ZrO 2 loading and thus Lewis acid sites concentration was found to have little impact on the ethanol conversion. Butadiene selectivity depends on the concentration of Lewis acid site, which in turn differs depending on the choice of SiO 2 support material. Wemore » observed a direct relationship between butadiene selectivity and concentration of Lewis acid sites. Butadiene selectivity decreases as the concentration of Lewis acid sites increases, which corresponds to an increase in ethanol dehydration to ethylene and diethyl ether. Additionally, adding H 2 to the feed had little effect on conversion while improving catalytic stability; however, selectivity to butadiene decreased. Lastly, catalyst regenerability was successfully demonstrated for several cycles.« less
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  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 0926-3373; PII: S0926337318304855
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Applied Catalysis. B, Environmental
Additional Journal Information:
Journal Volume: 236; Journal Issue: C; Journal ID: ISSN 0926-3373
Research Org:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org:
Country of Publication:
United States
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Ethanol; Butadiene; Biomass; Single-Step; SiO2Ag/ZrO2/SiO2acidity; Regeneration
OSTI Identifier: