Alcohol decomposition by reverse spillover
- Univ. of Colorado, Boulder, CO (United States)
Temperature-programmed desorption (TPD) was used to study methanol, ethanol, and 1-propanol decomposition on Al[sub 2]O[sub 3] and Ni/Al[sub 2]O[sub 3] catalysts. These alcohols adsorb on the Al[sub 2]O[sub 3] support of Ni/Al[sub 2]O[sub 3] and dehydrogenate by reverse spillover to the Ni surface. Thus, the presence of Ni dramatically increases their decomposition rates. Methanol adsorbed on Al[sub 2]O[sub 3] alone decomposes to form (CH[sub 3])[sub 2]O at lower temperature and CO, H[sub 2], and CO[sub 2] above 600 K. On Ni/Al[sub 2]O[sub 3], most CH[sub 3]OH dehydrogenates to form CO and H[sub 2]. Ethanol adsorbed on Al[sub 2]O[sub 3] mostly dehydrates to form C[sub 2]H[sub 4] and (C[sub 2]H[sub 5])[sub 2]O, but C[sub 2]H[sub 4]O and H[sub 2] are also observed. On Ni/Al[sub 2]O[sub 3], C[sub 2]H[sub 5]OH dehydrogenation to CO, H[sub 2], and surface carbon is the main reaction. 1-Propanol decomposes on Al[sub 2]O[sub 3] to form C[sub 3]H[sub 6], H[sub 2], (C[sub 3]H[sub 7])[sub 2]O, and C[sub 3]H[sub 6]O. When Ni is present, propanol decomposition to H[sub 2], CO, and surface carbon is the dominant process, but some C[sub 3]H[sub 6], C[sub 3]H[sub 6]O, and CO[sub 2] also form. On Al[sub 2]O[sub 3], the alcohols decomposition rates are in the order 1-C[sub 3]H[sub 7]OH > C[sub 2]H[sub 5]OH > CH[sub 3]OH, but on Ni/Al[sub 2]O[sub 3] the rates are almost identical. The increase in the decomposition rate of alcohols, when Ni is present, is attributed to alcohol diffusion along the Al[sub 2]O[sub 3] surface and decomposition on the Ni surface or at the Ni-Al[sub 2]O[sub 3] interface. The diffusivity of CH[sub 3]O on the Al[sub 2]O[sub 3] surface at 534 K is estimated to be larger than 6.6 x 10[sup [minus]11] cm[sup 2]/s. 38 refs., 7 figs., 3 tabs.
- OSTI ID:
- 5036122
- Journal Information:
- Journal of Catalysis; (United States), Vol. 144:1; ISSN 0021-9517
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
10 SYNTHETIC FUELS
ALUMINIUM OXIDES
CATALYTIC EFFECTS
ETHANOL
DECOMPOSITION
METHANOL
NICKEL COMPLEXES
PROPANOLS
CATALYST SUPPORTS
HETEROGENEOUS CATALYSIS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K
ALCOHOLS
ALUMINIUM COMPOUNDS
CATALYSIS
CHALCOGENIDES
CHEMICAL REACTIONS
COMPLEXES
HYDROXY COMPOUNDS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
TEMPERATURE RANGE
TRANSITION ELEMENT COMPLEXES
400201* - Chemical & Physicochemical Properties
100300 - Synthetic Fuels- Properties & Composition- (1990-)