Effect of deposited Pt particles on the surface charge of TiO/sub 2/ aqueous suspensions by potentiometry, electrophoresis, and labeled ion adsorption

Journal Article · Thu Jun 05 04:00:00 EDT 1986 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100403a035· OSTI ID:5697758

Jaffrezic-Renault, N; Pichat, P; Foissy, A; Mercier, R

Potentiometry, electrophoresis, and radiotracer technique have been used to study the charge density in different parts of the double layer at the TiO/sub 2/-electrolyte interface for powder samples supporting 0.5-10 wt % platinum as particles of homogeneous size (ca. 2 nm diameter). Less positive charge densities were measured by potentiometry for increasing Pt content; the value of point of zero charge decreases accordingly. More negative electrophoretic mobilities were found for the metal-loaded samples from pH 3 to pH approx.8; as a result the value of the point of zero zeta potential decreases with increasing Pt content. From a comparison between the surface charge density, the charge density of the diffuse part of the double layer, and the charge density of the counterions (determined from adsorption isotherms of labeled Na/sup +/ and Cl/sup -/ ions for TiO/sub 2/ and 10 wt % Pt/TiO/sub 2/), it is deduced that a part of the Cl/sup -/ ions form neutral adsorbed species at the Pt surface. Therefore, the changes observed in potentiometric titrations and electrophoretic mobilities are attributed to an increase in TiO/sub 2/ acidity induced by the Pt particles, which reflects the decreased TiO/sub 2/ electron density.

• Research Organization: Ecole Centrale de Lyon, Ecully, France
• OSTI ID: 5697758
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 90:12; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

08 HYDROGEN
080100 -- Hydrogen-- Production
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
AQUEOUS SOLUTIONS
CHALCOGENIDES
DATA
DISPERSIONS
ELECTROPHORESIS
ELEMENTS
EXPERIMENTAL DATA
INFORMATION
INTERFACES
ISOTOPE APPLICATIONS
METALS
MIXTURES
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PLATINUM
PLATINUM METALS
POTENTIOMETRY
SOLUTIONS
SURFACE PROPERTIES
SUSPENSIONS
TITANIUM COMPOUNDS
TITANIUM OXIDES
TITRATION
TRACER TECHNIQUES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS