Electrochemical reactivity of TiO2 nanoparticles adsorbed onto boron-doped diamond surfaces
Electrochemical reactivity of TiO2 nanoparticles adsorbed onto boron-doped diamond surfaces
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DOI：
10.1016/j.elecom.2004.09.006
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发表时间：
2004-11
影响因子：
5.4
通讯作者：
F. Marken;A. Bhambra;Duk Hyun Kim;R. Mortimer;Susan J. Stott
中科院分区：
文献类型：
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作者：
F. Marken;A. Bhambra;Duk Hyun Kim;R. Mortimer;Susan J. Stott
约 TiO2（锐钛矿）纳米颗粒。直径为 6-10 nm 的颗粒从酸性水溶液中吸附到多晶工业抛光的掺硼金刚石电极表面上。固定在电极表面后，TiO2 纳米粒子在真空中通过电子显微镜 (FEGSEM) 成像，当浸入 12 M LiCl 水溶液液膜中时通过原位扫描隧道显微镜 (STM) 成像。在不同的电解质介质中对 TiO2 颗粒的单层薄膜进行了伏安研究。掺硼金刚石作为惰性基质材料，可以研究磷酸盐缓冲溶液中 TiO2 颗粒的还原，并确定了还原-质子化过程中的两个不同步骤：(i) 与质子外层结合相关的广泛还原信号，以及 (ii) 与质子内层（或更深层）结合相关的更尖锐的第二还原信号。在含有不同量 HClO4 的 0.1 M NaClO4 水溶液中进行的伏安实验表明，TiO2 颗粒的还原与 Ti(III) 表面位点的形成一致，并伴随着质子的吸附。发生饱和并且可以确定表面位点的总量。讨论了还原后的 TiO2 表面电子转移过程的初步数据，例如析氢过程和马来酸至琥珀酸的双电子-双质子还原。
TiO2(anatase) nanoparticles of ca. 6–10 nm diameter are adsorbed from acidic aqueous solution onto polycrystalline industrially polished boron-doped diamond electrode surfaces. After immobilisation at the electrode surface, TiO2nanoparticles are imaged in vacuum by electron microscopy (FEGSEM) and when immersed in a liquid film of aqueous 12 M LiCl by in situ scanning tunnelling microscopy (STM). Mono-layer films of TiO2particles are studied voltammetrically in different electrolyte media. Boron-doped diamond as an inert substrate material allows the reduction of TiO2particles in phosphate buffer solution to be studied and two distinct steps in the reduction–protonation process are identified: (i) a broad reduction signal associated with the binding of an outer layer of protons and (ii) a sharper second reduction signal associated with the binding of an inner (or deeper) layer of protons. Voltammetric experiments in aqueous 0.1 M NaClO4with variable amounts of HClO4suggest that the reduction of TiO2particles is consistent with the formation of Ti(III) surface sites and accompanied by the adsorption of protons. Saturation occurs and the total amount of surface sites can be determined. Preliminary data for electron transfer processes at the reduced TiO2surface such as the dihydrogen evolution process and the two-electron–two-proton reduction of maleic acid to succinic acid are discussed.