Carbon Dot-Titanium Dioxide (CD/TiO2) Nanocomposites: Reusable Photocatalyst for Sustainable H2 Production via Photoreforming of Green Organic Compounds
Source abstract
Abstract
The present work focuses on TiO2 modification with carbon dots (CDs) using a hydrothermal process, which results in the synthesis of CD/TiO2 nanocomposite photocatalysts characterized by exceptional optoelectronic properties. The structural and physicochemical properties of the obtained nanocomposites, which contained varying amounts of CDs, were precisely assessed. HR-TEM analysis showed that the prepared nanocomposites consisted of rod-shaped TiO2 nanoparticles and CDs well-dispersed on their surface. The optical properties of the nanocomposites were studied using UV–vis diffuse reflectance spectroscopy. All CD/TiO2 samples presented decreased energy gap values compared with bare TiO2 samples; the band gap was further decreased as the CD concentration rose. Electrochemical measurements revealed that the presence of CDs improved the photocurrent response of the TiO2, presumably due to enhanced charge separation and decreased recombination. The synthesized nanomaterials were used as photocatalysts to produce hydrogen via the photoreforming of ethanol and glycerol green organic compounds, under 1-sun illumination. The photocatalytic experiments confirmed that the optimum loading of CDs corresponded to a percentage of 3% (w/w). Ethanol photoreforming led to a H2 production rate of 1.7 μmol∙min−1, while in the case of the glycerol sacrificial agent, the corresponding rate was determined to be 1.1 μmol∙min−1. The recyclability study revealed that the photocatalyst exhibited consistent stability during its reuse for hydrogen production in the presence of both ethanol and glycerol.
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Research context
OpenAlex topics: Carbon and Quantum Dots Applications · Advanced Photocatalysis Techniques · Advanced Nanomaterials in Catalysis
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
Affiliations
Institute of Nanoscience and Nanotechnology, National Center for Scientific Research “Demokritos”, Agia Paraskevi, 15341 Athens, Greece
School of Chemical Engineering, National Technical University of Athens, 9 Iroon Polytechniou St., Zografou, 15780 Athens, Greece
Department of Chemical Engineering, University of Western Macedonia, 50100 Kozani, Greece
Funding
Hellenic Foundation for Research and Innovation (HFRI) · European Union’s H2020 Programme iWAYS
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