Photoelectrochemical Performances and Potential Applications of TiO2 Nanotube Arrays Modified with Ag and Pt Nanoparticles

TiO2 nanotube arrays (NTAs) modified with Ag (Ag/TiO2) and Pt (Pt/TiO2) nanoparticles were fabricated by anodic oxidation combined with photoreduction and hydrothermal methods, respectively. Structures, element components and morphologies of TiO2, Ag/TiO2 and Pt/TiO2 NTAs were measured by X-ray diffraction diffractometer, X-ray photoelectron spectroscopy, scanning electron microscope and transmission electron microscope. The photoeletrochemical performances of TiO2, Pt/TiO2 and Ag/TiO2 NTAs were characterized by cyclic voltammetry and amperometry in phosphate buffer solution in absence and presence of glucose. Modifications of Ag and Pt nanoparticles play different roles in the photoelectrochemical process and have different potential applications. Ag nanoparticles decrease the photocurrent in buffer solution but increase the photocurrent response to organic compounds, which is fit for electrochemical detection of organic compounds due to the low background photocurrent and high photocurrent response. Ag/TiO2 NTAs achieve the best detection performance with sensitivity of 0.152 μA/μM and detection limit of 0.53 μM. On the contrary, Pt nanoparticles can enhance the photocurrent of TiO2 NTAs in buffer solution but decrease the photocurrent response to organic compounds, which are benefit for photocatalytic water splitting but not for photoelectrochemical detection.