The mechanism of NO interaction with nanosized Ru(Pd,Pt)-doped SnO2 was studied by electron paramagnetic resonance, Mo¨ssbauer, and electric resistance measurements. Three steps were proposed for the reaction between the semiconductor oxide and the gaseous component: (i) the formation of bielectronic oxygen vacancies (Vo) in SnO2; (ii) their single-ionization (Vo ¥) with injection of electrons into the SnO2 conduction band; (iii) the subsequent transfer of electrons from Vo ¥ to [Ru(Pd,Pt)]4+. The last process induces the formation of further oxygen vacancies which reduce the transition metal centers to lower oxidation states; the redox processes is enhanced and the electrical resistance in transition metal-doped SnO2 is stronger modified with respect to the undoped material.
Canevali, C., Mari, C., Mattoni, M., Morazzoni, F., Nodari, L., Ruffo, R., et al. (2005). Interaction of NO with nanosized Ru-, Pd-, and Pt-doped SnO2: Electron paramagnetic resonance, Mössbauer, and electrical investigation. JOURNAL OF PHYSICAL CHEMISTRY. B, CONDENSED MATTER, MATERIALS, SURFACES, INTERFACES & BIOPHYSICAL, 109(15), 7195-7202 [10.1021/jp040740k].
Interaction of NO with nanosized Ru-, Pd-, and Pt-doped SnO2: Electron paramagnetic resonance, Mössbauer, and electrical investigation
CANEVALI, CARMEN;MARI, CLAUDIO MARIA;MORAZZONI, FRANCA;RUFFO, RICCARDO;SCOTTI, ROBERTO
2005
Abstract
The mechanism of NO interaction with nanosized Ru(Pd,Pt)-doped SnO2 was studied by electron paramagnetic resonance, Mo¨ssbauer, and electric resistance measurements. Three steps were proposed for the reaction between the semiconductor oxide and the gaseous component: (i) the formation of bielectronic oxygen vacancies (Vo) in SnO2; (ii) their single-ionization (Vo ¥) with injection of electrons into the SnO2 conduction band; (iii) the subsequent transfer of electrons from Vo ¥ to [Ru(Pd,Pt)]4+. The last process induces the formation of further oxygen vacancies which reduce the transition metal centers to lower oxidation states; the redox processes is enhanced and the electrical resistance in transition metal-doped SnO2 is stronger modified with respect to the undoped material.
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