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Hiroshi Uetsuka

Publications and source records attributed to Hiroshi Uetsuka.

5 recordsLinked to original sources
PubMed2006

AFM observation of immobilized self-oscillating polymer.

Various types of nanocomponents have been developed to construct a nanodevice or nanomachine. Here, we add a new nanocomponent that has the function of self-oscillation. A thermoresponsive polymer carrying a Ru complex, a catalyst of the Belousov-Zhabotinsky reaction, was synthesized and immobilized on a glass plate. Periodic turbidity changes in the aqueous solution of the polymer were observed, and nanoscale self-oscillation of the immobilized polymer was observed by a scanning probe microscope.

Catalysis↗
PubMed2005

Photochemical reaction of trimethyl acetate on Pt/TiO2(110).

Nanometer-sized Pt particles were prepared on an atomically flat surface of rutile TiO(2). Trimethyl acetate (TMA) adsorbed on the Pt-modified surface was photochemically decomposed under ultraviolet light irradiation in a vacuum. Residing TMA anions were imaged by a scanning tunneling microscope to deduce the local rate of decomposition. Increasing the number density of Pt particles led to an enhancement of the initial reaction rate. The degree of this enhancement did not depend on the distance from the Pt particles.

Journal Article↗
PubMed2003

Photochemical charge transfer and trapping at the interface between an organic adlayer and an oxide semiconductor.

Identification of charge transfer and trapping sites on semiconducting oxide surfaces is of fundamental importance in furthering the field of heterogeneous photocatalysts. Using scanning tunneling microscopy, electron energy loss spectroscopy, and photodesorption, we observed both electron trapping and hole transfer events on the (110) surface of TiO2 rutile. UV irradiation of a saturated monolayer of trimethyl acetate (TMA) on TiO2(110) at room temperature resulted in hole transfer to the carboxylate group, followed by (CH3)3C-COO bond cleavage and desorption of CO2 and isobutene/isobutane. Hole transfer to TMA proceeded in the absence of a gas-phase electron scavenger (which is typically O2) because the accompanying photogenerated electrons could be trapped at the surface as Ti3+ cations bound to bridging OH groups. The extent of electron trapping, gauged by electron spectroscopy, correlated directly with the yields of photodesorption fragments resulting from the hole transfer channel. Charge at the Ti3+ sites was titrated in the dark via a reaction between O2 and the Ti3+-OH groups.

Journal Article↗