Synthesis and electrochemical properties of TiO_2anodiamond nanocomposite

摘要

Undoped nanodiamond (ND) powders were coated with TiO_2 through two steps: firstly Ti lay was deposited by cycled vacuum-feeding chemical vapour deposition from gaseous TiCl_4/H_2, and secondly an oxidation treatment was carried out in air. The structure and the morphology of the TiO_2/ND composite were characterized by Raman spectrum and transmission electron microscopy. The electrochemical properties of the TiO_2/ND powder electrode in a solution containing [Fe(CN)_6]~(3-/4-) or NO_2- were investigated. The results showed that a continuous coating consisting of Ti nanoparticles covered on ND particle after the deposition. The following oxidation at 500℃ resulted in the formation of anatase phase TiO_2 nanoparticles of about 10 nm. The electrochemical results confirmed that the TiO_2/ND powder electrode exhibited higher electrochemical activity than the pristine ND electrode, especially higher catalytic ability toward the oxidation of nitrite anions. Moreover, the TiO_2/ND powder electrode presented fast response towards nitrite oxidation with a detection limit of 0.55 μM and a linear range of 0.05 to 1.0 mM.