Photocatalytic hydrogenation of alkynes and alkenes with water over TiO/sub 2/. Pt-loading effect on the primary processes

Journal Article · Sun Jan 01 04:00:00 EST 1984 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j150662a027· OSTI ID:5628386

Anpo, M; Aikawa, N; Kubokawa, Y

Photoreactions of alkynes and alkenes with water have been investigated over Pt-loaded and unloaded TiO/sub 2/ in order to obtain information about the effects of Pt loading on photocatalytic reactions. With unloaded TiO/sub 2/, the major photoformed products are those formed by the hydrogen accompanied by the fission of the C identical with C or C=C bond of the reactants, while with Pt-loaded TiO/sub 2/, i.e., Pt/TiO/sub 2/, a significant enhancement of hydrogenation reaction without the bond fission is observed. In addition to those products, oxidation products such as CO and CO/sub 2/ are found. In contrast to the features with unloaded TiO/sub 2/, with Pt/TiO/sub 2/ there is no marked difference between the yields of the oxidation and reduction products. ESR (electron spin resonance) measurements show that photoformed electrons are accumulated as localized Ti/sup 3 +/ ions with unloaded TiO/sub 2/, whereas with Pt/TiO/sub 2/ electrons are easily transferred from TiO/sub 2/ to Pt particles. From these results and those of kinetic studies the significance of the close existence of electrons and holes for unloaded TiO/sub 2/ proposed in the preceding paper is confirmed. Furthermore, it has been shown that with Pt/TiO/sub 2/ a photoelectrochemical process is predominant, the reduction of H/sup +/ on Pt particles and the oxidation by OH on TiO/sub 2/ bringing about photohydrogenation without bond fission and formation of oxidation products, respectively. 11 references, 5 figures, 2 tables.

• Research Organization: Univ. of Osaka Prefecture, Japan
• OSTI ID: 5628386
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 88:18; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140505* -- Solar Energy Conversion-- Photochemical
Photobiological
& Thermochemical Conversion-- (1980-)
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400301 -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
ALKENES
ALKYNES
CARBON
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON MONOXIDE
CARBON OXIDES
CATALYSIS
CATALYSTS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL BONDS
CHEMICAL REACTION KINETICS
CHEMICAL REACTION YIELD
CHEMICAL REACTIONS
CHEMISTRY
DATA
DOUBLE BONDS
ELECTROCHEMISTRY
ELECTRON SPIN RESONANCE
ELEMENTS
EXPERIMENTAL DATA
HYDROCARBONS
HYDROGEN
HYDROGEN COMPOUNDS
HYDROGENATION
INFORMATION
KINETICS
MAGNETIC RESONANCE
METALS
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
OXIDATION
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PHOTOCHEMISTRY
PLATINUM
PLATINUM METALS
REACTION KINETICS
REDUCTION
RESONANCE
TEMPERATURE DEPENDENCE
TITANIUM COMPOUNDS
TITANIUM OXIDES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
WATER
YIELDS