S, N co-doped carbon quantum dots/TiO₂ nanocomposite as highly efficient visible light photocatalyst

Abstract

In this paper, we report on the preparation of S, N co-doped carbon quantum dots (CQDs)/TiO 2 nanocomposite using a hydrothermal process where S, N-CQDs were concurrently synthesized and anchored to the surface of the TiO 2 . The prepared nanocomposite was carefully characterized to identify the morphology and structure, crystallinity, chemical composition and optical properties. The photocatalytic activity of the nanocomposite was investigated for degradation of acid red 88 (AR88) under visible light irradiation. The capability of the S, N-CQDs/TiO 2 nanocomposite to remove AR88 (77.29%) was higher than that of pure TiO 2 (23.7%). In order to determine the influencing factors on the photocatalytic activity of the prepared nanocomposite, we studied various contents of the photocatalyst, the effect of pH and the content of H 2 O 2. Further investigations were conducted to reveal the mechanism of photocatalytic degradation using radical scavenging agents. The stability and reusability of the S, N-CQDs/TiO 2 photocatalyst was tested in four reaction cycles (870 min) which showed a 25% loss of photoactivity after the fourth photocatalytic reaction.

Visible-Light-Promoted Photocatalytic Applications of Carbon Dots: A Review

“…147 Rahbar et al synthesized S,N codoped CQD/TiO 2 nanocomposite for degradation of AR 88 (∼ 77%) under irradiation of visible light. 148 Kim reported the photocatalytic activity of perfluorinated silica-based fluorescent CD/TiO 2 toward MB dye degradation under visible light. 107 Xu et al observed that N-doped CQD loaded on P25 nanoparticles as N-CD/P25 have ∼13 times greater photocatalytic activity for degradation of RhB over P25 (less activity) under visible light irradiation.…”

Impact of Titanium Dioxide (TiO2) Modification on Its Application to Pollution Treatment—A Review

“…The synergistic effect increased the removal rate of bromoethane for 90 min from 54% of pure TiO2 to 94%. Rahbar et al [77] prepared S and N co-doped carbon quantum dots (CQDs)/TiO2 composites using the hydrothermal method. The degradation rate of acidic AR88 The lifetime of photogenerated electron-hole pairs and the region of light response to visible light are vital for TiO 2 to increase the value in pollutant treatment [67].…”

“…The synergistic effect increased the removal rate of bromoethane for 90 min from 54% of pure TiO 2 to 94%. Rahbar et al [77] prepared S and N co-doped carbon quantum dots (CQDs)/TiO 2 composites using the hydrothermal method. The degradation rate of acidic AR88 (azo dyes) under visible light irradiation was 54%, which was higher than that of pure TiO 2 .…”

A Highly Sensitive and Selective Probe for the Colorimetric Detection of Mn(II) Based on the Antioxidative Selenium and Nitrogen Co-Doped Carbon Quantum Dots and ABTS•+

“…What's more, due to the synergetic effect of multiple heteroatoms doping in the carbon lattice (Wang et al, 2015;Liu et al, 2020;Tripathi et al, 2020), the multielement (like N, Se, B, S, and P) co-doped CQDs have attracted much attention because of their novel properties different from single heteroatom doped CQDs and simple CQDs (Ruiqi et al, 2018;. Co-doped CQDs with different heteroatoms could afford more active sites and improve the fluorescent quantum yield (Ruiqi et al, 2018;Wei J. M. et al, 2018), tuning the photophysical characteristics of CQDs (Zhu et al, 2020), increasing electrical conductivity and specific surface area (Rahbar et al, 2019), obtaining dual-functional mode properties (Mohammed and Omer, 2020), and enhancing the properties of antioxidant capacity, analysis, detection, catalytic, electronic, and optical applications (Samantara et al, 2015;Li et al, 2016;Liu et al, 2019). Among the elements, the doping of nitrogen (N) into CQDs (N-CQDs) could not only improve the quantum yield and fluorescence efficiency but also provide active sites in the CQDs and impart unexpected surface properties to broaden the potential applications in the antioxidation, analysis, catalysis, and so on (Niu et al, 2015;Deng et al, 2018;Lu et al, 2018;Atchudan et al, 2019;Qi et al, 2019).…”