Physical Sciences and Mathematics Commons^™

An Effective Method For The Preparation Of High Temperature Stable Anatase Tio2 Photocatalysts, Rachel Fagan, Declan Mccormack, Suresh Pillai, Damian Synnott

Articles

An efficient, rapid and straightforward method for the preparation of nitrogen and fluorine (N, F) codoped high temperature stable anatase using a microwave pre-treatment is reported. Using a single source, ammonium fluoride (NH₄F) for both nitrogen and fluorine, effective doping of the precursor titanium isopropoxide (TTIP) was possible. These samples were characterised for their structural and optical properties using X-ray diffraction (XRD), Fourier transform IR (FTIR), Raman spectroscopy and UV-vis spectroscopy. In terms of the anatase to rutile transition enhancement using a novel microwave assisted technique, the sample prepared in a composition of 1:8 TiO₂: NH …

Improved High Temperature Stability Of Anatase Tio2 Photocatalysts By N, F, P Co-Doping, Rachel Fagan, Declan Mccormack, Steven Hinder, Suresh Pillai

Articles

Among the three commonly occurring phases (anatase, rutile, and brookite) of TiO2, the anatase form is reported to be the best photocatalyst due to the improved charge-carrier mobility and the greater number of surface hydroxyl groups. The anatase to rutile transition in titania photocatalysts usually occurs at a temperature between 500 °C to 700 °C. Development of a high temperature stable (above 1000 °C) anatase phase is important for various environmental applications (e.g. self-cleaning ceramic tiles, anti-microbial sanitary wares, etc.). In this study, the use of ammonium hexafluorophosphate as a single source dopant (method A) and urea, trifluoroacetic acid and …

A Simple Inexpensive Method For The Rapid Testing Of The Photocatalytic Activity Of Self Cleaning Surfaces, Andrew Mills, James Hepburn, David Hazafy, Christopher O'Rourke, Josef Krysa, Michal Baudys, Martin Zlamal, Hana Bartkova, Claire Hill, Kim Winn, Morten Simonsen, Erik Sogaard, Suresh Pillai, Nigel Leyland, Rachel Fagan, Frank Neumann, Christina Lampe, Tobias Graumann

Articles

A rapid semi-quantitative, inexpensive method,using a simple digital scanner and an indicator ink, suitable for use in the laboratory, or in the field, for assessing the photocatalytic activity of commerical photocatalytic self-cleaning materials such as glass, is described. The repeatability of the current method is found to be hight and better than many of the previously reported ISO photocatalyst tests.

Novel Microwave Assisted Synthesis Of Zns Nanomaterials, Suresh Pillai, Michael Seery, Damian Synnott, John Colreavy, Stephen Hinder

Articles

A novel ambient pressure microwave-assisted technique is developed in which silver and indium modified ZnS is synthesised. The as prepared ZnS is characterised by X-ray diffraction, UV-Vis spectroscopy, X-ray photoelectron spectroscopy and luminescence spectroscopy. This procedure produced crystalline materials with particle sizes below 10 nm. The synthesis technique leads to defects in the crystal which induce mid energy levels in the band gap and lead to indoor light photocatalytic activity. Increasing the amount of silver causes a phase transition from cubic blende to hexagonal phase ZnS. In a comparative study, when the ZnS cubic blende is heated in a conventional …

A Highly Efficient Tio2-Xcx Nano-Heterojunction Photocatalyst For Visible-Light Induced Antibacterial Applications, Vinodkumar Etacheri, Michael Seery, Stephen Hinder, Georg Michlits, Suresh Pillai

Articles

Visible-light-induced antibacterial activity of carbon-doped anatase-brookite titania nano-heterojunction photocatalysts are reported for the first time. These heterostructures were prepared using a novel low temperature (100 °C) non-hydrothermal low power microwave (300 W) assisted method. Formation of interband C 2p states was found to be responsible for the band gap narrowing of the carbon doped heterojunctions. The most active photocatalyst obtained after 60 minutes of microwave irradiation exhibits a 2-fold higher visible-light induced photocatalytic activity in contrast to the standard commercial photocatalyst Evonik-Degussa P-25. Staphylococcus aureus inactivation rate constant for carbon-doped nano-heterojunctions and the standard photocatalyst was 0.0023 and -0.0081 min …

Uv And Visible Light Activated Tio2 Photocatalysis Of 6-Hydroxymethyluracil, A Model Compound For The Potent Cyanotoxin Cylindrospermopsin, Cen Zhao, Miquel Pelaez, Dionysios Dionysiou, Suresh Pillai, John Byrne, Kevin O'Shea

Articles

TiO₂ photocatalyses of 6-hydroxymethyl uracil (6-HOMU) a model compound for the potent cyanotoxin, cylindrospermopsin (CYN), were carried out employing visible and UV irradiation using different non-metal doped TiO₂ materials, nitrogen and fluorine-TiO₂ (NF-TiO₂), phosphorus and fluorine-TiO₂ (PF-TiO₂) and sulfur-TiO₂ (S-TiO₂). The model compound was readily degraded under UV TiO₂ photocatalysis with pseudo-first-order rate constants (k) of 2.1, 1.0, and 0.44 h⁻¹ for NF-TiO₂, PF-TiO₂ and S-TiO₂, respectively. Under visible light activated (VLA), NF-TiO₂ was the most active photocatalyst, PF-TiO …

Nitrogen And Copper Doped Solar Light Active Tio2 Photocatalysts For Water Decontamination, Mike Fisher, Donal Keane, Pilar Fernandez-Ibanez, John Colreavy, Stephen Hinder, Kevin Mcguigan, Suresh Pillai

Articles

A novel class of photocatalytic coating capable of degrading bacterial and chemical contaminants in the presence of visible sunlight wavelengths was produced by depositing a stable photocatalytic TiO

2 film on the internal lumen of glass bottles via a sol–gel method. This coating was prepared in either undoped form or doped with nitrogen and/or copper to produce visible light-active TiO2 films which were annealed at 600 ◦C and were characterized by Raman and X-ray photoelectron spectroscopy. The presence of doped and undoped TiO2 films was found to accelerate the degradation of methylene blue in the presence of natural sunlight, while …

A Systematic Study Of The Effect Of Silver On The Chelation Of Formic Acid To A Titanium Precursor And The Resulting Effect On The Anatase To Rutile Transformation Of Tio2, Nicholas Nolan, Michael Seery, Steve Hinder, Linda Healy, Suresh Pillai

Articles

Anatase to rutile transition in an unmodified synthetic titania usually occurs at a temperature range of 600 – 700 °C. Various methods such as addition of metallic and non-metallic dopants and modifying the precursor have previously been reported to influence the anatase to rutile transition temperature. In the current study, the effect of addition of increasing amounts of silver to the extent of chelation of a formate group to a titanium precursor and the resulting effects on the transformation of anatase to rutile has been studied. The addition of silver (0, 1, 3 and 5 mol %) on the anatase …

Highly Visible Light Active Tio2-Xnx Heterojunction Photocatalysts, Vinodkumar Etacheri, Michael Seery, Steven Hinder, Suresh Pillai

Articles

Nitrogen doped anatase-rutile heterojunctions are successfully synthesized through an ethylene-diaminetetraacetic acid (EDTA) modified sol-gel process.An FT-IR study of EDTA modified TiO2 gel confirms the existence of an ionic intermediate (as indicated by a Δν value of 233 cm-1).Differential scanning calorimetry (DSC), X-ray diffraction (XRD), and Raman spectroscopy are employed to study the phase evolution, phase purity, and crystallite size of samples. Formations of O-Ti-N and N-Ti-N bonds in calcined samples are confirmed using XPS and FT-IR spectro- scopy. AllEDTAmodified samples show significantly higher visible light photocatalytic activity than the unmodified sample. The most active nitrogen doped heterojunction obtained at 400C …

Spectroscopic Investigation Of The Anatase-To-Rutile Transformation Of Sol-Gel Synthesised Tio2 Photocatalysts, Nicholas Nolan, Suresh Pillai, Michael Seery

Articles

Among the three major phases in titania, anatase is reported to be a better photocatalytically active phase. Anatase to rutile transformations, under normal conditions, usually occurs at a temperatue range of 600- 700 °C. Various chemical additives have previously been employed to extend the anatase transition to higher temperatures. Effect of employing various concentrations of formic acid and water on phase transition has systematically been studied by XRD, FTIR and Raman spectroscopy. A considerably higher anatase phase (41%) has been obtained at 800 ºC and 10% anatase composition is retained after annealing the materials at 900 ºC for the optimised …

A Novel Tiq2-Assisted Solar Photocatalytic Batch-Process Disinfection Reactor For The Treatment Of Biological And Chemical Contaminants In Domestic Drinking Water In Developing Countries, E. F. Duffy, F. Al Touati, S. C. Kehoe, O. A. Mcloughlin, L. W. Gill, W. Gernjak, I. Oller, M. I. Maldonado, S. Malato, John Cassidy, R. H. Reed, K. G. Mcguigan

Articles

he technical feasibility and performance of photocatalytic Ti02 coatings in batch-process solar disinfection (SODIS) reactors to improve potability of drinking water in developing countries have been studied. Borosilicate glass and PET plastic SODIS reactors fitted with flexible plastic inserts coated with Ti02 powder were shown to be 2(Jt1o and 25% more effective, respectively, than standard SODIS reactors for the inactivation of E. coli K12. Isopropanol at 100 ppm concentration levels was observed to be completely photodegraded after 24 h continuous exposure to lOG mW/cm2 simulated sunlight in a similar solar photocatalytic disinfector (SPC-DIS) reactor. The technique for p roducing the …