Selective growth of Ti3+/TiO2/CNT and Ti3+/TiO2/C nanocomposite photocatalysts for enhanced visible-light utilization to degrade organic pollutants by lowering the bandgap of TiO2

Abstract

A convenient route was developed for the selective preparation of two stable nanocomposites, Ti3+/TiO2/CNT (labeled as TTOC-1 and TTOC-3) and Ti3+/TiO2/carbon layer (labeled as TTOC-2), from the same precursor by varying the amount of single-walled carbon nanotubes used in the synthesis. TiO2 is an effective photocatalyst; however, its wide bandgap limits its usefulness to the UV region. As a solution to this problem, our prepared nanocomposites exhibit a small bandgap and wide visible-light (VL) absorption because of the introduction of carbonaceous species and Ti3+ vacancies. The photocatalytic efficiency of the nanocomposites was examined via the degradation of methylene blue dye under VL. Excellent photocatalytic activity of 83%, 98%, and 93% was observed for TTOC-1, TTOC-2, and TTOC-3 nanocomposites within 25 min. In addition, the photocatalytic degradation efficiency of TTOC-2 toward rhodamine B was 71% and for methyl orange (MO) dye was 28% under similar experimental conditions, after 25 min. Higher reusability and structural integrity of the as-synthesized photocatalyst were confirmed within five consecutive runs by photocatalytic test and X-ray diffraction analysis, respectively. The resulting nanocomposites provide new insights into the development of VL-active and stable photocatalysts with high efficiencies.

CO2 photocatalytic reduction with robust and stable metal–organic framework: a review

“…On top of that, it is difficult to tune the absorption wavelength of conventional semiconductors because they already have intrinsic bandgap energy. For instance, TiO 2 is mainly used for UV light photocatalysis owing to its own wide bandgap (3-3.2 eV) [20]. ZnO and CdS are not stable in water specially under light illumination, which is preventing them to be applied for actual application usage [21,22].…”