In situ infrared study of methanol synthesis from H{sub 2}/CO over Cu/SiO{sub 2} and Cu/ZrO{sub 2}/SiO{sub 2}
- Lawrence Berkeley National Lab., CA (United States). Chemical Sciences Div.
The presence of Cu greatly accelerates the rate of formate hydrogenation to methoxide species, a process in which methylenebisoxy species are observed as intermediates. Cu also significantly promotes the reductive elimination of methoxide species as methanol. Thus, methanol synthesis over Cu/ZrO{sub 2}/SiO{sub 2} is envisioned to occur on ZrO{sub 2}, with the primary role of Cu being the dissociative adsorption of H{sub 2}. The spillover of atomic H onto ZrO{sub 2} provides the source of hydrogen needed to hydrogenate the carbon-containing species. Spillover of absorbed CO from Cu to zirconia facilitates formate formation on zirconia at lower temperatures than in the absence of Cu. The reductive elimination of methoxide species appears to be the slow step in methanol formation by CO hydrogenation. The lower rate of methanol synthesis over Cu/ZrO{sub 2}/SiO{sub 2} from CO as compared to CO{sub 2} hydrogenation is attributed to the lack of water formation in the former reaction, preventing facile release of methoxide by hydrolysis. The enhanced rate of methanol synthesis from CO over Cu/ZrO{sub 2}/SiO{sub 2} as compared to Cu/SiO{sub 2} is attributed to the lower energy-barrier (formate) pathway available on Cu/ZrO{sub 2}/SiO{sub 2}.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 659077
- Journal Information:
- Journal of Catalysis, Vol. 178, Issue 1; Other Information: PBD: 15 Aug 1998
- Country of Publication:
- United States
- Language:
- English
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