Improving carbon coated TiO2 films with a TiCl4 treatment for photocatalytic water purification

Using a simple thermal decomposition route, carbon-TiO2 hybrid films have been synthesized from a catechol-TiO2 surface complex. The coated films display enhanced visible region absorption, owing to the thin (~2 nm) layer of carbon encapsulating the TiO2. While photocatalytically active under visible light alone, it is demonstrated that the activity of the carbon coated films can be improved further by a hydrolytic treatment with TiCl4, leading to the introduction of small TiO2 particles (5-10nm) and doping of chlorine into the structure. The combination of the carbon layer and TiCl4 treatment gives increased photocatalytic performance for the photodegradation of dyes, phenolic pollutants and the reduction of toxic Cr(VI) to relatively benign Cr(III). In addition, the carbon coated films show improved bactericidal activity under UV irradiation, and hence have been successfully tested against the most common types of pollutant present in potential drinking waters

Sequential Ionic Layer Adsorption Reaction Formation of LaVO4-TiO2 Nanocomposites for Photocatalytic Water Treatment

Lanthanum Vanadate (LaVO4) has been successfully deposited as a thin conformal layer onto the surface of P25 TiO2 particles immobilized on the surface of macroscopic glass beads. Using a simple sequential ionic layer adsorption reaction (SILAR) method, the LaVO4 layer is deposited in situ with good control over the loading. Both the prepared composites and individual LaVO4 and TiO2 materials have been thoroughly characterized by x-ray diffraction, electron microscopies, x-ray photoelectron spectroscopy. The coated bead samples have been applied in the photocatalytic degradation of the model organic pollutant 4-chlorophenol, with the optimal LaVO4 loading displaying ~3x higher degradation of the pollutant than the pristine P25 sample. Using electrochemical and spectroscopic methods, band energies for both materials and the composite have been determined, and a provisional mechanism for degradation proposed upon the basis of this band alignment and upon scavenging experiments. ## .dat files ## Please note, files with the filename extension '.dat' are SEM EDX data files. They are opened in the instruments' software, called Oxford Instruments Aztec.Odling, Gylen. (2020). Sequential Ionic Layer Adsorption Reaction Formation of LaVO4-TiO2 Nanocomposites for Photocatalytic Water Treatment, [dataset]. University of Edinburgh. School of Chemistry. https://doi.org/10.7488/ds/2810

Bismuth titanate modified and immobilized TiO2 photocatalysts for water purification: broad pollutant scope, ease of re-use and mechanistic studies

Deposition of titanium dioxide (TiO2) coatings onto glass beads from a P25 enriched sol of titanium butoxide is described. This method gives a robust and stable covering, to which small bismuth containing clusters of 1-5 nm have been introduced using a simple and scalable sequential ionic layer adsorption reaction (SILAR) method. This bismuth-modified TiO2 coating has been proven to show significant improvements over the pristine TiO2 samples for a variety of different pollutants including intermediates in consumer product manufacture, pesticides, drugs and explosives. Using scavenger tests, the mechanism of degradation for each of the pollutant molecules tested has been probed, and a thorough discussion of the differences presented. The applicability of the system has also been assessed, with ease of re-use of the photocatalyst-bead apparatus investigated through recycling tests.Odling, Gylen. (2018). Bismuth titanate modified and immobilized TiO2 photocatalysts for water purification: broad pollutant scope, ease of re-use and mechanistic studies, [dataset]. University of Edinburgh. School of Chemistry. https://doi.org/10.7488/ds/2452

Improving carbon coated TiO2 films with a TiCl4 treatment for photocatalytic water purification

Table of contents 1. Electrochemistry Contains electrochemical impedance data for the samples .pfr, .dfr openable in Metrohm FRA, .mot files may be imported as ASCII 2. Photocatalysis Contains photocatalytic testing data for the samples .jws files openable in JASCO spectra manager Corresponding files also available as .txt 3. Uv-vis Contains uv-vis absorption data for the samples .jws files openable in JASCO spectra manager Corresponding files also available as .txt 4. XPS Contains X-ray photoelectron spectroscopy data for the samples .vms file openable in CasaXPS 5. XRD Contains X-ray diffraction traces for the samples .brml files openable in Bruker XRD supported systems Corresponding files also available as .txtUsing a simple thermal decomposition route, carbon-TiO2 hybrid films have been synthesized from a catechol-TiO2 surface complex. The coated films display enhanced visible region absorption, owing to the thin (~2 nm) layer of carbon encapsulating the TiO2. While photocatalytically active under visible light alone, it is demonstrated that the activity of the carbon coated films can be improved further by a hydrolytic treatment with TiCl4, leading to the introduction of small TiO2 particles (5-10nm) and doping of chlorine into the structure. The combination of the carbon layer and TiCl4 treatment gives increased photocatalytic performance for the photodegradation of dyes, phenolic pollutants and the reduction of toxic Cr(VI) to relatively benign Cr(III). In addition, the carbon coated films show improved bactericidal activity under UV irradiation, and hence have been successfully tested against the most common types of pollutant present in potential drinking waters.`Odling, Gylen. (2017). Improving carbon coated TiO2 films with a TiCl4 treatment for photocatalytic water purification, [dataset]. University of Edinburgh, School of Chemistry. http://dx.doi.org/10.7488/ds/2070

BiVO4-TiO2 composite photocatalysts for dye degradation formed using the SILAR method - open data

Composite photocatalyst films have been fabricated by depositing BiVO4 upon TiO2 via a sequential ionic layer adsorption reaction (SILAR) method. The photocatalytic materials were investigated by XRD, TEM, UV-vis diffuse reflectance, ICP-OES, XPS, photoluminescence and Mott-Schottky analyses. SILAR processing was found to deposit monoclinic-scheelite BiVO4 nanoparticles onto the surface, giving successive improvements in the films’ visible light harvesting. Electrochemical and valence band XPS studies revealed that the prepared heterojunctions have a type II band structure, with the BiVO4 conduction band and valence band lying cathodically shifted from those of TiO2. The photocatalytic activity of the films was measured by the decolourisation of the dye rhodamine 6G using λ > 400 nm visible light. It was found that 5 SILAR cycles was optimal, with a pseudo 1st order rate constant of 0.004 min-1. As a reference material the same SILAR modification has been made to an inactive wide band gap ZrO2 film, where the mismatch of conduction and valence band energies disallows charge separation. The photocatalytic activity of the BiVO4-ZrO2 system was found to be significantly reduced, highlighting the importance of charge separation across the interface. The mechanism of action of the photocatalysts has also been investigated, in particular the effect of self-sensitisation by the model organic dye and the ability of the dye to inject electrons into the photocatalysts conduction band.Odling, Gylen. (2016). BiVO4-TiO2 composite photocatalysts for dye degradation formed using the SILAR method - open data, [dataset]. University of Edinburgh. School of Chemistry. http://dx.doi.org/10.7488/ds/1396

Sequential Ionic Layer Adsorption and Reaction (SILAR) deposition of Bi4Ti3O12 on TiO2: an enhanced and stable photocatalytic system for water purification

A new method to produce bismuth titanate – titanium dioxide composites by modification of a TiO2 film deposited on a variety of different glass substrates is reported. Using a simple SILAR method, BiOBr may be deposited upon TiO2 surfaces, which upon heating forms a closely intercalated structure of bismuth titanate (Bi4Ti3O12, BTO) and TiO2. This new method expands the scope of the SILAR process, which is typically restricted to materials which can be formed from soluble precursors. This composite material has undergone a thorough materials characterisation to confirm the absence of the BiOBr precursor, and the formation of the new bismuth titanate phase. The electronic structure of the heterojunction formed has also been investigated by valence band XPS and diffuse reflectance measurements, and a plausible band structure proposed. The immobilised composites have then been applied to the photocatalytic degradation of organic pollutants and bactericidal testing, as well as stability tests and identification of the key reactive species. Further photocatalytic studies have been carried out on this material in a synthetic wastewater medium, taking a step towards application under real-world conditions.Odling, Gylen; Chatzisymeon, Efthalia; Robertson, Neil. (2018). Sequential Ionic Layer Adsorption and Reaction (SILAR) deposition of Bi4Ti3O12 on TiO2: an enhanced and stable photocatalytic system for water purification, [dataset]. University of Edinburgh. School of Chemistry. http://dx.doi.org/10.7488/ds/2285