Enhanced Photoelectrochemical Activity of a Hierarchical-Ordered TiO2 Mesocrystal and Its Sensing Application on a Carbon Nanohorn Support Scaffold

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• 作者：Hong Dai ; Shupei Zhang ; Zhensheng Hong ; Xiuhua Li ; Guifang Xu ; Yanyu Lin ; Guonan Chen
• 刊名：Analytical Chemistry
• 出版年：2014
• 出版时间：July 1, 2014
• 年：2014
• 卷：86
• 期：13
• 页码：6418-6424
• 全文大小：373K
• ISSN：1520-6882

文摘

A ternary hybrid was developed through interaction between a hierarchical-ordered TiO₂ and a thiol group that was obtained by in situ chemical polymerization of l-cysteine on the carbon nanohorn (CNH) superstructure modified electrode. Herein, unique-ordered TiO₂ superstructures with quasi-octahedral shape that possess high crystallinity, high porosity, oriented subunit alignment, very large specific surface area, and superior photocatalytic activity were first introduced as a photosensitizer element in the photoelectrochemical determination. Additionally, the assembly of hierarchical-structured CNHs was used to provide an excellent electron-transport matrix to capture and transport an electron from excited anatase to the electrode rapidly, hampering the electron鈥揾ole recombination effectively, resulting in improved photoelectrochemical response and higher photocatalytic activity in the visible light region. Owing to the dependence of the photocurrent signal on the concentration of electron donor, 4-methylimidozal, which can act as a photogenerated hole scavenger, an exquisite photoelectrochemical sensor was successfully fabricated with a wide linear range from 1 脳 10^鈥? to 1 脳 10^鈥?0 M, and the detection limit was down to 30 pM. The low applied potential of 0.2 V was beneficial to the elimination of interference from other reductive species that coexisted in the real samples. More importantly, the mesocrystal was first introduced in the fabricating of a biosensor, which not only opens up a new avenue for biosensors manufactured based on mesocrystal materials but also provides beneficial lessons in the research fields ranging from solar cells to photocatalysis.