Effect of surface adsorptions of aliphatic alcohols and silver ion on the photocatalytic activity of TiO[sub 2] suspended in aqueous solutions

Journal Article · Wed Jan 27 23:00:00 EST 1993 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100106a018· OSTI ID:6566492

Ohtani, B; Nishimoto, Seiichi ^[1]

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1. Kyoto Univ. (Japan)

Photoirradiation of the light of wavelength >300 nm onto suspensions of titanium (IV) oxide (TiO[sub 2], anatase, TiO[sub 2](A), and rutile TiO[sub 2](R)) in aqueous solution of silver salts and aliphatic alcohols led to the evolution of molecular oxygen (O[sub 2]), the deposition of silver metal (Ag) onto the surface of TiO[sub 2] and the oxidation of alcohols. The product distribution was studied by using some aliphatic alcohols (methanol, ethanol, 2-propanol, and tert-butyl alcohol) and inorganic and organic silver salts. Kinetic analyses were performed with an aqueous suspension containing 2-propanol and silver sulfate. Dependence of the initial formation rates of products (O[sub 2], acetone, and Ag) on the concentration of 2-propanol in suspension (C[sub p]) was analyzed on the assumption of a mechanism including reductive and oxidative trappings of pairs of photoexcited electron (e[sup [minus]])- positive hole (h[sup +]) by surface-adsorbed substrates. The mechanism implies facile recombination of the pair in the absence of the appropriate surface-adsorbed substrates. The mechanism implies facile recombination of the pair in the absence of the appropriate surface-adsorbed substrates, which react with the pair to produce free active species, e[sup [minus]] and h[sup +], with sufficient ability for subsequent redox reactions. It is presumed that coverage of surface sites with 2-propanol via Langmuirian adsorption determines the distribution of free h[sup +] generated by the reductive trapping by silver ion (Ag[sup +]). The C[sub p] dependence of the rate in TiO[sub 2](A) suspension was consistent with the proposed mechanism and some kinetic and adsorption parameters were obtained. 19 refs., 7 figs., 2 tabs.

• OSTI ID: 6566492
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 97:4; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500* -- Photochemistry
ACETONE
ADSORPTION
ALCOHOLS
AQUEOUS SOLUTIONS
BUTANOLS
CATALYSIS
CATALYTIC EFFECTS
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
DEPOSITION
DISPERSIONS
ELEMENTS
ETHANOL
HYDROXY COMPOUNDS
KETONES
KINETICS
METALS
METHANOL
MIXTURES
NONMETALS
ORGANIC COMPOUNDS
OXIDATION
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PROPANOLS
REACTION KINETICS
RECOMBINATION
REDOX REACTIONS
REDUCTION
SILVER
SOLUTIONS
SORPTION
SORPTIVE PROPERTIES
SURFACE PROPERTIES
SUSPENSIONS
TITANIUM COMPOUNDS
TITANIUM OXIDES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
TRAPPING