Synergistic effects of the hybridization between boron-doped carbon quantum dots and n/n-type g-C3N4 homojunction for boosted visible-light photocatalytic activity

• Published in: Environmental science and pollution research international 2022-06, Vol.29 (27), p.41272-41292
• Main Authors: Phang, Sue Jiun, Lee, Jiale, Wong, Voon-Loong, Tan, Lling-Lling, Chai, Siang-Piao
• Format: Article
• Language: English
• Subjects: Anions; Aquatic ecosystems; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Boron; Carbon; Carbon nitride; Catalytic activity; Chemical composition; Dyes; Earth and Environmental Science; Ecotoxicology; Energy gap; Environment; Environmental Chemistry; Environmental Health; Environmental perception; Environmental science; Free radicals; Homojunctions; Hybridization; Hydroxyl radicals; Industrial wastewater; Irradiation; Light irradiation; Nanocomposites; Optical properties; Optimization; Photocatalysis; Photocatalysts; Photodegradation; Quantum dots; Research Article; Rhodamine; Scavenging; Superoxide anions; Synergistic effect; Waste Water Technology; Wastewater; Water Management; Water Pollution Control
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-021-18253-0

Dye wastewater has raised a prevalent environmental concern due to its ability to prevent the penetration of sunlight through water, thereby causing a disruption to the aquatic ecosystem. Carbon quantum dots (CQDs) are particularly sought after for their highly tailorable photoelectrochemical and optical properties. Simultaneously, graphitic carbon nitride (g-C 3 N 4 ) has gained widespread attention due to its suitable band gap energy as well as excellent chemical and thermal stabilities. Herein, a novel boron-doped CQD (BCQD)-hybridized g-C 3 N 4 homojunction (CN) nanocomposite was fabricated via a facile hydrothermal route. The optimal photocatalyst sample, 1-BCQD/CN (with a 1:3 mass ratio of boron to CQD) accomplished a Rhodamine B (RhB, 10 mg/L) degradation efficiency of 96.8% within 4 h under an 18 W LED light irradiation. The kinetic rate constant of 1.39 × 10 –2  min −1 achieved by the optimum sample was found to be 3.6- and 2.8-folds higher than that of pristine CN and un-doped CQD/CN, respectively. The surface morphology, crystalline structure, chemical composition and optical properties of photocatalyst samples were characterized via TEM, FESEM-EDX, XRD, FTIR, UV–Vis DRS and FL spectrometer. Based on the scavenging tests, it was revealed that the photogenerated holes (h + ), superoxide anions (∙O 2 – ) and hydroxyl radicals (∙OH) were the primary reactive species responsible for the photodegradation process. Overall, the highly efficient 1-BCQD/CN composite with excellent photocatalytic activity could provide a cost-effective and robust means to address the increasing concerns over global environmental pollution.