Stott Susan J, Mortimer Roger J, Dann Sandie E, Oyama Munetaka, Marken Frank
Department of Chemistry, Loughborough University, Loughborough, Leicestershire, UK LE113TU.
Phys Chem Chem Phys. 2006 Dec 14;8(46):5437-43. doi: 10.1039/b610391j. Epub 2006 Oct 26.
Titanium carbide (TiC) nanoparticles are readily deposited onto tin-doped indium oxide (ITO) electrodes in the form of thin porous films. The nanoparticle deposits are electrically highly conducting and electrochemically active. In aqueous media (at pH 7) and at applied potentials positive of 0.3 V vs. SCE partial anodic surface oxidation and formation (at least in part) of novel core-shell TiC-TiO2 nanoparticles is observed. Significant thermal oxidation of TiC nanoparticles by heating in air occurs at a temperature of 250 degrees C and leads first to core-shell TiC-TiO2 nanoparticles, next at ca. 350 degrees C to TiO2 (anatase), and finally at temperatures higher than 750 degrees C to TiO2 (rutile). Electrochemically and thermally partially oxidized TiC nanoparticles still remain very active and for some redox systems electrocatalytically active. Scanning and transmission electron microscopy (SEM and TEM), temperature dependent XRD, quartz crystal microbalance, and voltammetric measurements are reported. The electrocatalytic properties of the core-shell TiC-TiO2 nanoparticulate films are surveyed for the oxidation of hydroquinone, ascorbic acid, and dopamine in aqueous buffer media. In TiC-TiO2 core-shell nanoparticle films TiO2 surface reactivity can be combined with TiC conductivity.
碳化钛（TiC）纳米颗粒易于以薄多孔膜的形式沉积在掺锡氧化铟（ITO）电极上。纳米颗粒沉积物具有高导电性和电化学活性。在水介质（pH值为7）中，当施加相对于饱和甘汞电极（SCE）为正0.3V的电位时，观察到部分阳极表面氧化并形成了新型核壳结构的TiC-TiO₂纳米颗粒（至少部分形成）。在空气中加热时，TiC纳米颗粒在250℃会发生显著的热氧化，首先生成核壳结构的TiC-TiO₂纳米颗粒，接着在约350℃时生成TiO₂（锐钛矿型），最后在高于750℃的温度下生成TiO₂（金红石型）。经电化学和热部分氧化的TiC纳米颗粒仍然非常活跃，并且对于某些氧化还原体系具有电催化活性。本文报道了扫描电子显微镜（SEM）、透射电子显微镜（TEM）、变温X射线衍射（XRD）、石英晶体微天平以及伏安测量结果。研究了核壳结构的TiC-TiO₂纳米颗粒薄膜对水缓冲介质中对苯二酚、抗坏血酸和多巴胺氧化的电催化性能。在TiC-TiO₂核壳纳米颗粒薄膜中，TiO₂的表面反应活性可以与TiC的导电性相结合。
