Enhanced Photocatalysis of Graphene and TiO₂ Dual-Coupled Carbon Nanofibers Post-treated at Various Temperatures

Abstract

Graphene and titanium dioxide (TiO 2 ) were coupled to a conducting polymer substrate to generate graphene− TiO 2 carbon nanofibers (GTCNs) using an electrospinning method with a post-thermal treatment process. The photocatalytic activities of GTCNs for the purification of selected toxic organic pollutants under visible-light illumination were higher than those of three reference photocatalysts (i.e., TiO 2 -, graphene-, and polyacrylonitrile-based carbon nanofibers). The photocatalytic activities of GTCNs increased with increasing treatment temperature from 300 to 400 °C and then decreased gradually with further increases to 500 and 600 °C, indicating that there is an optimum post-treatment temperature. The photocatalytic degradation efficiencies for the target pollutants over GTCNs post-treated at 400 °C under visible-light-emitting-diode (visible-LED) irradiation were lower than those obtained using a conventional daylight lamp. However, visible-LEDs were suggested as energy-potent photon sources for photocatalysis of gaseous toxic organic chemicals over GTCNs.

Microstructure and photocatalytic activity of electrospun carbon nanofibers decorated by TiO 2 nanoparticles from hydrothermal reaction/blended spinning

“…Electrospun nanofibers, as the forefront of advanced fibrous materials, combining the fine flexibility, low density, extremely high aspect ratio, ease of scalable synthesis from various materials, possessed favorable foreground applications in various fields [22][23][24]. As a result of their outstanding potential, many efforts had been made to use electrospun nanofibers for the preparation of CNFs@TiO 2 composites [1,[25][26][27].…”

Nanostructured Photocatalysts Based on Different Oxidized Graphenes for VOCs Removal

“…22 A 4-fold increase of the degradation rate was observed and it was related both to the more-efficient electron transfer and to the affinity of the substrate to the GO and rGO sheets. In another study, Chun et al 23 reported the graphene and TiO 2 incorporation into carbon nanofibers and their performance under visible-LED irradiation: the initial concentration resulted as a crucial parameter for the photocatalytic treatment of gas-phase target pollutants. According to our previous work, 7,11 photocatalytic oxidation has been proven to be a promising technology for air purification, and nanostructured mats based on electrospun nanofibers offer a proper support in the production of active filtering media in order to combine the physical activity of the media with the chemical degradation of harmful pollutants.…”

“…Just a few papers refer to gas-phase experiments, − and before focusing on them, it is very important to observe that, in gas-phase photocatalysis, the dominant photodegradation mechanism is not always straightforward and, more generally, a myriad of radical-based reactions are potentially available. Moreover, it must be emphasized that the local environment, as well as the target species, govern all these reactions.…”

“…A 4-fold increase of the degradation rate was observed and it was related both to the more-efficient electron transfer and to the affinity of the substrate to the GO and rGO sheets. In another study, Chun et al reported the graphene and TiO 2 incorporation into carbon nanofibers and their performance under visible-LED irradiation: the initial concentration resulted as a crucial parameter for the photocatalytic treatment of gas-phase target pollutants.…”

Recent development of centrifugal electrospinning

“…Because of their large specific surface area, high porosity, and tunable mechanical properties, nanofibers have broad application in many fields, including bioengineered structures, air and water filtration, electronics, drug delivery, fuel cells, biomedical tissue engineering, building materials, and smart clothing . However, nanofibers produced by traditional methods present some problems, including their toxic solvents and low output.…”