Photocatalytic isotopic exchange between cyclopentane and deuterium over a bifunctional Pt/TiO/sub 2/ catalyst

Journal Article · Sat Oct 31 23:00:00 EST 1981 · J. Catal.; (United States)

OSTI ID:5604029

Courbon, H; Herrmann, J M; Pichat, P

Cyclopentane-deuterium isotopic exchange (CDIE) was performed at -10/sup 0/C with a C/sub 5/H/sub 10//D/sub 2/ ratio of approx. =6.4% over an illuminated (300 to 410 nm) 0.5 wt% Pt/anatase catalyst. A selectivity in C/sub 5/H/sub 9/D of approx. =90% was found with a total quantum yield of approx. =1.8%. The photocatalytic nature of CDIE under these conditions was established from these results: (i) no CDIE in the absence of photons of wavelengths shorter than the absorption edge of anatase or when TiO/sub 2/ was replaced by SiO/sub 2/, whereas the CDIE observed at higher temperatures (from 0/sup 0/C) without uv light mainly produced multiply exchanged cyclopentane, (ii) a linear CDIE rate-illumination time relationship was found, and (iii) an experiment carried out with the same catalyst sample showed that it was capable of exchanging, in successive runs, without decrease in activity, an amount of C/sub 5/H/sub 10/ 78 times greater than that corresponding to a photoinduced stoichiometric surface reaction. By contrast, CDIE over pure TiO/sub 2/ was limited and was only observed for hydroxylated specimens pretreated in D/sub 2/ at 300/sup 0/C. It is concluded that (i) CDIE occurred on anatase between weakly adsorbed C/sub 5/H/sub 10/ and OD/sup -/ ions activated by the trapping of photoproduced positive holes, and (ii) Pt, besides attracting the support-free electrons which decreased the recombination of electron-hole pairs, regenerated the titania OD/sup -/ ions after their isotopic exchange, which involved D/sub 2/ dissociative adsorption on the metal and subsequent migration of D atoms to the oxide. This constitutes an example of bifunctional heterogeneous photocatalysis.

• Research Organization: Inst. de Recherches sur la Catalyse, Cedex, France
• OSTI ID: 5604029
• Journal Information: J. Catal.; (United States), Journal Name: J. Catal.; (United States) Vol. 72:1; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

090110* -- Hydrocarbon Fuels-- Properties-- (1979-1989)
10 SYNTHETIC FUELS
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500 -- Photochemistry
ALKANES
CATALYSIS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMISTRY
CYCLOALKANES
DATA
DEUTERIUM
ELEMENTS
EXPERIMENTAL DATA
HYDROCARBONS
HYDROGEN
HYDROGEN ISOTOPES
INFORMATION
ISOTOPES
ISOTOPIC EXCHANGE
LIGHT NUCLEI
METALS
NONMETALS
NUCLEI
NUMERICAL DATA
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMISTRY
PLATINUM
PLATINUM METALS
STABLE ISOTOPES
TITANIUM COMPOUNDS
TITANIUM OXIDES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS