Bifunctional g-C3N4/carbon nanotubes/WO3 ternary nanohybrids for photocatalytic energy and environmental applications.

Ternary nanohybrids based on mesoporous graphitic carbon nitride (g-C3N4) were synthesized and presented for developing stable and efficient Hydrogen (H2) production system. Based on photocatalytic activity, optimization was performed in three different stages to develop carbon nanotubes (CNTs) and WO3 loaded g-C3N4 (CWG-3). Initially, the effect of exfoliation was investigated, and a maximum specific surface area of 100.77 m2/g was achieved. 2D-2D interface between WO3 and g-C3N4 was targeted and achieved, to construct a highly efficient direct Z-scheme heterojunction. Optimized binary composite holds the enhanced activity of about 2.6 folds of H2 generation rates than the thermally exfoliated g-C3N4. Further, CNT loading towards binary composite in an optimized weight ratio enhances the activity by 6.86 folds than the pristine g-C3N4. Notably, optimized ternary nanohybrid generates 15,918 µmol h-1. g-1cat of molecular H2, under natural solar light irradiation with 5 vol% TEOA as a sacrificial agent. Constructive enhancements deliver remarkable H2 production and dye degradation activities. Results evident that, the same system can be useful for pilot-scale energy generation and other photocatalytic applications as well.

Photocatalytic hydrogen production by ternary heterojunction composites of silver nanoparticles doped FCNT-TiO2.

Silver nanoparticles doped with FCNT-TiO2 heterogeneous catalyst was prepared via one-step chemical reduction process and their efficacy was tested for hydrogen production under solar simulator. Crystallinity, purity, optical properties, and morphologies of the catalysts were examined by X-Ray diffraction, Raman spectroscopy, UV-Visible diffuse reflectance spectra, and Transmission Electron Microscopy. The chemical states and interface interactions were studied by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The optimized catalyst showed 19.2 mmol g-1 h-1 of hydrogen production, which is 28.5 and 7 times higher than the pristine TiO2 nanoparticles and FCNT-TiO2 nanocomposite, respectively. The optimized catalyst showed stability up to 50 h under the solar simulator irradiation. The natural solar light irradiated catalyst showed ~2.2 times higher hydrogen production rate than the solar simulator irradiation. A plausible reaction mechanism of Ag NPs/FCNT-TiO2 photocatalyst was elucidated by investigating the beneficial co-catalytic role of Ag NPs and FCNTs for enhanced hydrogen production.

Highly efficient solar light-driven photocatalytic hydrogen production over Cu/FCNTs-titania quantum dots-based heterostructures.

The need for clean and eco-friendly energy sources has increased enormously over the years due to adverse impacts caused by the detrimental fossil fuel energy sources on the environment. This work reports the safest and most efficient route for hydrogen generation using solar light receptive functionalized carbon nanotubes-titania quantum dots (FCNT-TQDs) as photocatalysts under the influence of solar light irradiation. Predominantly, dual capability of CNT as co-catalyst and photo-sensitizer reduced the recombination rate of charge carriers, and facilitated the efficient light harvesting. The bulk production of hydrogen via water harvesting is considered, wherein photocatalyst synthesized was tuned by the optimum addition of copper to achieve higher production rate of hydrogen up to 54.4 mmol h-1g-1, nearly 25-folds higher than that of pristine TiO2 quantum dots. Addition of copper has a crucial role in improving the rate of hydrogen generation. The ternary composite exhibited 5.4-times higher hydrogen production compared to FCNT-TQDs composite.