Photodegradation of Rhodamine B over a novel photocatalyst of feather keratin decorated CdS under visible light irradiation

Abstract

A novel photocatalyst of feather keratin (FK)-decorated CdS was synthesized by a simple co-precipitation method. Scanning electron microscopy (SEM) showed that the particle sizes of FK/CdS nanocomposites were smaller than pure CdS. The coexistence of FK and CdS in the photocatalysts was further confirmed by Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The results of photocatalytic experiments demonstrated that the FK/CdS composites exhibit significantly enhanced photocatalytic activity for the photocatalytic degradation of RhB compared with pure CdS under visible light irradiation. The enhanced photocatalytic activity of the FK/CdS composites can be attributed to the similar affinity between FK and RhB, which can effectively separate the photogenerated electron-hole pairs. This method not only improves the photocatalytic activity of CdS, but also reduces the environmental pollution of waste feathers. In addition, the possible degradation mechanism of RhB is proposed.

Preparation of carbon spheres supported CdS photocatalyst for enhancement its photocatalytic H 2 evolution

“…We know that CdS semiconductor with a direct band gap of 2.4 eV displays superior optical, photophysical and photochemical properties [10]. However, there exist some problems in using CdS.…”

High Efficiency Epitaxial‐Graphene/Silicon‐Carbide Photocatalyst with Tunable Photocatalytic Activity and Bandgap Narrowing

“…On the other hand, the VB edge potential of 6H‐SiC is less positive than the standard oxidation potentials of •OH/OH − (+2.38 V vs NHE), confirming that the photogenerated holes could not oxidize OH – to yield •OH. Thus, the holes can directly oxidize RhB through the defects at EG on SiC . With improvement of quality and quantity of graphene and heterojunction interface layers in EG/SiC system, i.e., with increasing I 2D / I G , the overall reaction rate can be improved; thereby the system will show better photocatalytic activity.…”

“…This superoxide anion radical •O 2 − oxidize RhB molecules and decompose RhB into CO 2 and H 2 O . On the other hand, the VB edge potential of 6H‐SiC is less positive than the standard oxidation potentials of •OH/OH − (+2.38 V vs NHE), confirming that the photogenerated holes could not oxidize OH – to yield •OH. Thus, the holes can directly oxidize RhB through the defects at EG on SiC .…”

“…In presence of EG, electrons transfer from the SiC conduction band to EG Fermi level, which is energetically favorable since the electron affinity of 6H‐SiC (≈3.45 eV), is lower than the work function of EG (monolayer and bilayer, ≈4.14 eV), greatly alleviates recombination of electrons and holes in SiC. The transferred electrons in the Fermi level of EG then react with the O 2 molecules to generate the active oxygen species (super oxide ions •O 2 − ) because the potential of EG/EG •− (monolayer/bilayer, ≈−0.3 V vs NHE), is more negative than the standard redox potentials of O 2 /•O 2 − (−0.28 V vs NHE) . This superoxide anion radical •O 2 − oxidize RhB molecules and decompose RhB into CO 2 and H 2 O .…”

“…The transferred electrons in the Fermi level of EG then react with the O 2 molecules to generate the active oxygen species (super oxide ions •O 2 − ) because the potential of EG/EG •− (monolayer/bilayer, ≈−0.3 V vs NHE), is more negative than the standard redox potentials of O 2 /•O 2 − (−0.28 V vs NHE) . This superoxide anion radical •O 2 − oxidize RhB molecules and decompose RhB into CO 2 and H 2 O . On the other hand, the VB edge potential of 6H‐SiC is less positive than the standard oxidation potentials of •OH/OH − (+2.38 V vs NHE), confirming that the photogenerated holes could not oxidize OH – to yield •OH.…”