Chemistry-Driven Signal Transduction in a Mesoporous Pt/TiO2 System
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- 作者：Eduard G. Karpov ; Mohammad A. Hashemian ; Suhas K. Dasari
- 刊名：The Journal of Physical Chemistry C
- 出版年：2013
- 出版时间：August 1, 2013
- 年：2013
- 卷：117
- 期：30
- 页码：15632-15638
- 全文大小：423K
- 年卷期：v.117,no.30(August 1, 2013)
- ISSN：1932-7455
文摘
We report on two distinct modes of catalytic oxidation of hydrogen to water on a mesoporous Pt/TiO2 structure with an electrically continuous 15 nm mesh-like Pt layer. The structure supported a continuous oxidation of hydrogen to water, starting at room temperature in 160 Torr O2 and also performed as a chemical鈥揺lectrical transducer. Along with the usual fast reaction over the nanodispersed Pt, a 1200 times slower mode of the reaction is revealed by studying the reaction-induced currents. This slow mode leads to a surprisingly strong stationary current at electron yield 0.04, electromotive force 鈭?.32 V, and short-circuit current density 12 渭A/cm2 at room temperature. This phenomenon is explained by involvement of both Pt and TiO2 phases in the slow reaction flow, where a proton spillover mechanism of the observed electromotive force is suggested. The overall reaction current kinetics contains many autonomously formed features including peaks and alterations of the charge flow direction to manifest competition between various surface reaction regimes. These studies provide interesting opportunities for smart chemical sensors, transducers, and novel analytical tools.