Adsorption and Reaction of Methanol over CeO_X(100) Thin Films

Journal Article · Wed Mar 13 00:00:00 EDT 2013 · Langmuir

DOI:https://doi.org/10.1021/la400295f· OSTI ID:1109698

Albrecht, P; Mullins, D

Methanol was adsorbed on oxidized and reduced CeO_X(100) thin films to probe the active sites and reaction selectivity of these surfaces compared to those of CeO_X(111). Roughly twice as much methoxy was formed on oxidized CeO₂(100) compared to that formed on CeO₂(111). In addition to more methoxy, hydroxyl is also more stable on CeO₂(100). Unlike on CeO₂(111), however, methanol on CeO₂(100) produced CO, CO₂, and H₂ in addition to water and formaldehyde. The behavior of CeO₂(100) is related to its surface structure, which provides greater access to Ce cations and therefore more active adsorption sites and more highly undercoordinated Ce and O. The undercoordinated O may explain the enhanced dehydrogenation activity leading to CO and H₂ formation. The reduction of ceria leads to increased methanol uptake on both CeO_{2 – X}(100) and CeO_{2 – X}(111). However, although the uptake doubled on reduced CeO_{2 – X}(111) compared to the oxidized surface, it increased by only 10% on reduced CeO_{2 – X}(100) compared to that on fully oxidized CeO₂(100). Reduction of both surfaces leads to a greater production of CO and H₂. Reaction on all surfaces progresses rapidly from methoxy to products. Lastly, there is no spectroscopic evidence of formyl or formate intermediates. On CeO_X(100), carbonate is detected that decomposes into CO₂ at high temperature.

• Research Organization: Brookhaven National Lab. (BNL), Upton, NY (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 1109698
• Report Number(s): BNL-102832-2013-JA
• Journal Information: Langmuir, Vol. 29, Issue 14; ISSN 0743-7463
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English