Heterogeneous photocatalytic reactions of organic acids and water: new reaction paths besides the photo-kolbe reaction
The heterogeneous photocatalytic reactions of acetic, propionic, and butyric acids were studied on several kinds of powdered semiconductors, mainly TiO/sub 2/. The influence of Ag/sup +/ as an electron acceptor, and the dependence of the reactions on the kind of semiconductor and pH, were investigated. The ratio of yields of hydrogen to hydrocarbon depends strongly on pH. At neutral or alkaline pH, hydrocarbon stops being evolved and only hydrogen is evolved. It is concluded that the pH dependence of the valence band position of the semiconductor and the concentration of OH/sup -/ ion control the reaction paths. From the pH dependence of methane production from acetic acid the valence band of anatase is estimated to be located more deeply by 0.1 eV than that of rutile. The results of product analysis and the complete decomposition of acetic acid to CO/sub 2/ show that there exist new reaction paths in which water is an oxidizing agent. Reaction schemes of these organic acids are proposed.
- Research Organization:
- Inst. for Molecular Science, Myodaiji, Japan
- OSTI ID:
- 6935731
- Journal Information:
- J. Phys. Chem.; (United States), Vol. 88:11
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
14 SOLAR ENERGY
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ACETIC ACID
PHOTOCHEMICAL REACTIONS
BUTYRIC ACID
HYDROCARBONS
CHEMICAL PREPARATION
HYDROGEN PRODUCTION
PROPIONIC ACID
SEMICONDUCTOR MATERIALS
CATALYTIC EFFECTS
TITANIUM OXIDES
WATER
CATIONS
EXPERIMENTAL DATA
HETEROGENEOUS CATALYSIS
PH VALUE
POWDERS
REACTION KINETICS
SILVER COMPOUNDS
CARBOXYLIC ACIDS
CATALYSIS
CHALCOGENIDES
CHARGED PARTICLES
CHEMICAL REACTIONS
DATA
HYDROGEN COMPOUNDS
INFORMATION
IONS
KINETICS
MATERIALS
MONOCARBOXYLIC ACIDS
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
SYNTHESIS
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
080106* - Hydrogen- Production- Biosynthesis & Photochemical Processes
140505 - Solar Energy Conversion- Photochemical
Photobiological
& Thermochemical Conversion- (1980-)
400500 - Photochemistry