Outstanding visible light photocatalysis by nano-TiO2 hybrids with nitrogen-doped carbon quantum dots and/or reduced graphene oxide

Baragau, Ioan-Alexandru, Buckeridge, John, Nguyen, Kiem, Heil, Tobias, Sajjad, Tariq, Thomson, Stuart A. J., Rennie, Alistair, Morgan, David John ORCID: https://orcid.org/0000-0002-6571-5731, Power, Nicholas P, Nicolae, Sabina, Titirici, Maria-Magdalena, Dunn, Steven and Kellici, Suela 2023. Outstanding visible light photocatalysis by nano-TiO2 hybrids with nitrogen-doped carbon quantum dots and/or reduced graphene oxide. Journal of Materials Chemistry A: materials for energy and sustainability 11 (18) 10.1039/D2TA09586F

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Abstract

Historically, titanium dioxide (TiO2) has been one of the most extensively studied metal oxide photocatalysts; however, it suffers from a large bandgap and fast charge recombination. We report the use of green, rapid, single-step continuous hydrothermal flow synthesis for the preparation of TiO2, and TiO2 hybrids with reduced graphene oxide (rGO) and/or N-doped carbon quantum dots (NCQDs) with significant enhancement in photocatalytic activity. Using a solar light generator under ambient conditions with no extra oxygen gas added, we observed the evolution reaction of the model pollutant (methylene blue) in real time. Tailoring of the light absorption to match that of the solar spectrum was achieved by a combination of materials of nano-TiO2 hybrids of nitrogen-doped carbon quantum dots and graphene in its reduced form with a photocatalytic rate constant of ca. 25 × 10−5 s−1. Using a diversity of state-of-the-art techniques including high-resolution transmission electron microscopy, transient photoluminescence, X-ray photoelectron spectroscopy and high accuracy, sophisticated hybrid density functional theory calculations we have gained substantial insight into the charge transfer and modulation of the energy band edges of anatase due to the presence of graphene or carbon dots, parameters which play a key role in improving drastically the photocatalytic efficiencies when compared to pristine titania. More importantly, we prove that a combination of features and materials displays the best photocatalytic behaviour. This performance is delivered in a greener synthetic process that not only produces photocatalytic materials with optimised properties and tailored visible light absorption and efficiency but also provides a path to industrialization.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Chemistry Cardiff Catalysis Institute (CCI)
Publisher:	Royal Society of Chemistry
ISSN:	2050-7488
Date of First Compliant Deposit:	13 April 2023
Date of Acceptance:	16 March 2023
Last Modified:	20 Mar 2024 02:30
URI:	https://orca.cardiff.ac.uk/id/eprint/158858

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