Carbon-nanotube/TiO2 materials synthesized by a one-pot oxidation/hydrothermal route for the photocatalytic production of hydrogen from biomass derivatives

Abstract

Hybrid photocatalysts containing different amounts of carbon nanotubes (CNTs) and TiO2 were synthesized by a one-pot oxidation/hydrothermal route and used for hydrogen production from aqueous solutions of methanol and glycerol under UV-LED irradiation. Platinum nanoparticles (1 wt%) were used as co-catalysts. Different techniques, namely X-ray diffraction, transmission electron microscopy, photoluminescence, electrochemical impedance, diffuse reflectance UV–vis spectroscopy, thermogravimetry and N2 adsorption were used to characterize the prepared materials. The presence of both CNTs and Pt has a great influence on the photocatalytic activity of CNT-Pt/TiO2 nanocomposites. The presence of CNTs extend the photo-response of TiO2 to the visible region, narrow its bandgap energy, enhance the charge mobility and reduce the electron/hole recombination. The hybrid material loaded with 1 wt% of CNT (1%CNT-Pt/TiO2), displayed the highest photoactivity for hydrogen production under UV-LED (384 nm) irradiation using both methanol and aqueous glycerol solutions, with 2327 and 2091 μmol g−1 of H2 produced at the end of 2 h of irradiation, respectively. Also, this material showed excellent photostability during at least three cycles.