Growth of Highly Single Crystalline IrO₂ Nanowires and Their Electrochemical Applications

다국어 초록 (Multilingual Abstract)

<P>We present the facile growth of highly single crystalline iridium dioxide (IrO<SUB>2</SUB>) nanowires on SiO<SUB>2</SUB>/Si and Au substrates via a simple vapor phase transport process under atmospheric pressure without any catalyst. Particularly, high-density needle-like IrO<SUB>2</SUB> nanowires were readily obtained on a single Au microwire, suggesting that the melted surface layer of Au might effectively enhance the nucleation of gaseous IrO<SUB>3</SUB> precursors at the growth temperature. In addition, all the electrochemical observations of the directly grown IrO<SUB>2</SUB> nanowires on a single Au microwire support favorable electron-transfer kinetics of [Fe(CN<SUB>6</SUB>)]<SUP>4–/3–</SUP> as well as Ru(NH<SUB>3</SUB>)<SUB>6</SUB><SUP>3+/2+</SUP> at the highly oriented crystalline IrO<SUB>2</SUB> nanowire surface. Furthermore, stable pH response is shown, revealing potential for use as a miniaturized pH sensor, confirmed by the calibration curve exhibiting super-Nernstian behavior with a slope of 71.6 mV pH<SUP>–1</SUP>.</P><P><B>Graphic Abstract</B>
<IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2012/jpccck.2012.116.issue-34/jp306900m/production/images/medium/jp-2012-06900m_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jp306900m'>ACS Electronic Supporting Info</A></P>