Black titanium dioxide nanocolloids by laser irradiation in liquids for visible light photo-catalytic/electrochemical applications

• Published in: Applied surface science Vol. 623; p. 157096
• Main Authors: Raveendran Nair, Pooja, Rosa Santiago Ramirez, Claudia, Angel Gracia Pinilla, Miguel, Krishnan, Bindu, Avellaneda Avellaneda, David, Fabian Cienfuegos Pelaes, Rene, Shaji, Sadasivan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 30-06-2023
• Subjects: Black titania; Defect rich titania; Photoelectrochemistry; Pulsed laser irradiation in liquids; Visible light photocatalysis; Pulsed laser irradiation in liquids; Photoelectrochemistry; Defect rich titania; Black titania; Visible light photocatalysis
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2023.157096

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•Defects rich black titania by 532 nm laser irradiation of TiO2 in different liquids.•Structure and phase analysis confirm the change from anatase to rutile.•Morphologies modified and visible light absorption enhanced by irradiation.•Visible light photocatalytic degradation studies on methylene blue.•Photoelectrochemical studies show efficient oxygen evolution reaction.
The discovery of defect induced TiO2 nanoparticles with enhanced visible light absorption has sparked an outburst of interest for visible energy applications. Here we report the formation of black titanium dioxide (BTO) nanoparticles in de-ionized water (DW), isopropyl alcohol (IPA) and DW-IPA mixture (1:1) using pulsed laser irradiation in liquids. X-ray diffraction showed the transformation of the major anatase phase in WTO (white TiO2) to rutile for BTO by irradiation. The presence of these phases was further confirmed by Raman spectroscopy. Transmission electron microscopy (TEM) was utilized for the morphology and structural confirmation. Scanning electron microscopy (SEM) showed the existence of nanoparticles with mixed shapes and sizes. X-ray photoelectron spectroscopy (XPS) acquired information on the chemical states present as well as elemental composition where shifts in Ti 2p as well as O 1s peaks are observed for BTO. Reduced bandgap and enhanced visible light absorption are observed in BTO by diffuse reflectance spectroscopy (DRS). Photocatalytic degradation studies showed superior organic dye decay activity under visible light for BTO. Photoelectrocatalytic activity of BTO films in neutral pH showed selectivity for oxygen evolution reaction (OER). These results show a facile fabrication of defect rich metal oxide nanomaterials with enhanced visible light activity.