CQD/TiO2 nanocomposite photocatalyst for efficient visible light-driven purification of wastewater containing methyl orange dye

• Published in: Materials chemistry and physics Vol. 278; p. 125583
• Main Authors: Shafique, Muhammad, Mahr, Muhammad Shabir, Yaseen, Muhammad, Bhatti, Haq Nawaz
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 15-02-2022; Elsevier BV
• Subjects: Carbon quantum dot; Catalysts; Catalytic support; Dyes; Methyl orange; Nanocomposite; Nanocomposites; Photocatalysis; Photocatalyst; Photocatalytic activity; Photodegradation; Purification; Quantum dots; Sol-gel processes; Stability; Tauc plot; TiO2; Titanium dioxide; Wastewater; X ray photoelectron spectroscopy; Tauc plot; Photocatalytic activity; Carbon quantum dot; Catalytic support; Nanocomposite; Methyl orange; Photocatalyst; TiO2
• ISSN: 0254-0584; 1879-3312
• DOI: 10.1016/j.matchemphys.2021.125583

In this study, we report a cost effective and facile synthesis method for preparing carbon quantum dot incorporated TiO2 nanocomposite (CQD/TiO2) for rapid photodegradation of methyl orange (MO) under direct and indirect sun irradiations. In practice, TiO2 nanosols and CQD were prepared by sol-gel and hydrothermal routes, subsequently their nanocomposites (CQD/TiO2) by sonication assisted mixing process at ambient conditions. Different analyses like XRD, FTIR and SEM/EDX. TEM, XPS, Zeta-potential were employed to characterize the prepared catalysts. CQD/TiO2 prepared in the weight ratio of 1:10 of CQD and TiO2 exhibited optimized MO-photodegradation (three folded to the activity of pure TiO2) in direct sunlight exposures at pH 11. The results show that variations in the initial concentration and pH of MO solution as well as catalyst loadings have a significant impact on the photocatalytic performance of CQD/TiO2. Similar MO-percentage degradations for five consecutive cycles highlighted its long-term catalytic stability and good reusability potential. Because of good visible-light photocatalytic efficiency, profound catalytic-stability, and reusability for dyes photocatalysis, CQD/TiO2 nanohybrid is a potential candidate for photocatalytic purification of textile and other organic based wastewater under direct and indirect solar light exposures.
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•A novel, cost-effective and facile synthesis method for preparing CQD/TiO2 nanocomposite is developed.•CQD/TiO2 displays 2 times more Methyl orange-photodegradation than pure TiO2.•CQD/TiO2 is catalytically stable for several cycles.•First and second order kinetic models are well validated for these systems.