Diethylenetriamine-assisted in situ synthesis of TiO2 nanoparticles on carbon nanotubes with well-defined structure and enhanced photocatalytic performance

Abstract

A simple diethylenetriamine (DETA)-assisted solvothermal method is utilized for in situ synthesis of TiO₂ nanoparticles on carbon nanotubes (CNTs), fabricating TiO₂/CNT composites with well-defined structure and enhanced photocatalytic activity for the degradation of methylene blue (MB). It is found that the DETA plays an important role on the structure, photoelectrochemistry and catalytic performance of the TiO₂/CNT composites. Particularly, the TiO₂/CNT catalyst obtained in the presence of 0.02 mL DETA exhibits both a low adsorption capacity and high photodegrading activity for MB removal under the UV-light irradiation, proving the uniform and well-dispersed TiO₂ particles loaded. Systematic characterization reveals the strong interaction and high electron-transfer efficiency between TiO₂ and CNT in the sample with the assistance of DETA. Besides, a DETA-assisted formation mechanism of the TiO₂/CNT composite has also been proposed in this study: DETA will work as a connecting bridge to facilitate the uniform adsorption of Ti⁴⁺ on the surface of CNT. With the increase of solvothermal temperature, the adsorbed Ti⁴⁺ gradually in situ crystallizes to form the TiO₂/CNT composite. The DETA-assisted in situ synthesis could be expected to be a promising method for the preparation of metal oxides supported on carbon materials with well-defined structure and superior photocatalytic or photoelectrochemical properties.