Carbon quantum dots modified Bi ₂ WO ₆ nanoflowers for enhancing photocatalytic activity: an experimental and DFT study

Abstract

Carbon quantum dots (CQDs) decorated Bi 2 WO6 nanocomposites were successfully synthesised by a facile hydrothermal method. The prepared samples were characterised by the XRD, FESEM, TEM, XPS, UV-vis DRS, photocurrent and photoluminescence (PL) techniques. The DRS, photocurrent, PL spectra measurements reveal that the introduction of CQDs could broaden the absorption edge and accelerate the separation and transportation efficiency of carriers. Moreover, a reasonable charge transfer approach was given out based on the calculated work function and the differential charge difference. The CQDs/Bi 2 WO 6-2 sample provides the optimal activity for photodegradation of CIP under simulated sunlight irradiation. It is hopeful that this work not only gives a reference for the design of CQDs/Bi 2 WO 6 composites, but also provides some mechanistic insights into enhanced photoactivity.

Rational Design of an Efficient S-Scheme Heterojunction of CdS/Bi2WO6–S Nanocomposites for Photocatalytic CO2 Reduction

“…−0.6 and 1.8 V versus NHE, respectively. Because Bi 2 WO 6 –S has a relatively higher work function (5.07 eV) compared to that of CdS (4.90 eV), the formation of an effective interface between Bi 2 WO 6 –S and CdS lead to a simultaneous transfer of the electrons from CdS to Bi 2 WO 6 –S, which can be evidenced from the XPS spectrum of the 0.5 CdS/Bi 2 WO 6 –S nanocomposite by showing a positive shift in Cd 3d and S 2p compared to those in bare CdS as well as a negative shift in Bi 4f and W 4f compared to those in bare Bi 2 WO 6 . − A built-in electric field, with positively charged CdS and negatively charged Bi 2 WO 6 –S, is thus formed. Besides, up- or downward band bending occurs at the interface of CdS and Bi 2 WO 6 –S, respectively.…”

Fabrication of new composite NCuTiO2/CQD for photocatalytic degradation of ciprofloxacin and pharmaceutical wastewater treatment: degradation pathway, toxicity assessment

“…Finally, long-life holes are produced at the TiO 2 surface and the photo-catalytic properties increase 23 , 24 . Currently, a large variety of CQD modified photo-catalysts have been reported, such as CQDs/TiO 2 25 , CQDs/Bi 2 WO 6 26 , CQDs/g-C 3 N 4 27 and Fe 2 O 3 @ZnO/N-CQDs 14 , 28 . Therefore, according to the mentioned characteristics for CQD, our study is to fabricate CQD decorated N, Cu -doped TiO 2 in photocatalysis treatment of CIP antibiotic and pharmaceutical wastewater under visible light.…”