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Articles 1 - 12 of 12

Full-Text Articles in Analytical Chemistry

Photocatalytic Properties Of G-C3n4–Tio2 Heterojunctions Under Uv And Visible Light Conditions, Rachel Fagan, Declan Mccormack, Steven J. Hinder, Suresh Pillai Apr 2016

Photocatalytic Properties Of G-C3n4–Tio2 Heterojunctions Under Uv And Visible Light Conditions, Rachel Fagan, Declan Mccormack, Steven J. Hinder, Suresh Pillai

Articles

Graphitic carbon nitride (g-C3N4) and titanium dioxide (TiO2) were chosen as a model system to investigate photocatalytic abilities of heterojunction system under UV and visible light conditions. The use of g-C3N4 has been shown to be effective in the reduction in recombination through the interaction between the two interfaces of TiO2 andg-C3N4. A simple method of preparing g-C3N4 through the pyrolysis of melamine was employed, which was then added to undoped TiO2 material to form the g-C3N4–TiO2 system. These materials were then fully characterized by X-ray diffraction (XRD), Brunauer Emmett Teller (BET), and various spectroscopic techniques including Raman, X-ray photoelectron …


An Effective Method For The Preparation Of High Temperature Stable Anatase Tio2 Photocatalysts, Rachel Fagan, Declan Mccormack, Suresh Pillai, Damian Synnott Mar 2016

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 Jan 2016

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 …


The Bench Synthesis Of Silver Nanostructures Of Variable Size And An Introductory Analysis Of Their Optical Properties, Aoife Power, Tony Betts, John Cassidy Jan 2013

The Bench Synthesis Of Silver Nanostructures Of Variable Size And An Introductory Analysis Of Their Optical Properties, Aoife Power, Tony Betts, John Cassidy

Articles

A laboratory practical was designed for use by both undergraduate and second level students to demonstrate the synthesis and characterisation of tuneable silver colloids. It clearly illustrates the novel optical properties of silver nanoparticles compared to the bulk metal. The synthesis is both rapid and repeatable, and can be conducted on the laboratory bench at room temperature.


Preparation And Characterization Of A Composite Of Gold Nanoparticles And Single-Walled Carbon Nanotubes And Its Potential For Heterogeneous Catalysis, Anne Shanahan, James Sullivan, Mary Mcnamara, Hugh Byrne Oct 2011

Preparation And Characterization Of A Composite Of Gold Nanoparticles And Single-Walled Carbon Nanotubes And Its Potential For Heterogeneous Catalysis, Anne Shanahan, James Sullivan, Mary Mcnamara, Hugh Byrne

Articles

A single-walled carbon nanotube-supported gold nanoparticle composite was prepared and characterized by X-ray diffraction, scanning transmission electron microscopy/scanning electron microscopy/transmission electron microscopy, energy-dispersive X-ray analysis, atomic absorption spectroscopy, nitrogen adsorption, Raman spectroscopy, and ultraviolet-visible spectroscopy. The Au particles were found to be crystalline, with a well-defined and narrow particle-size distribution, centered around 7 nm. The activity and selectivity of the composite for solventless aerobic oxidation of a secondary alcohol were examined, and a conversion efficiency of 95% was obtained.


Evaluation Of A Naive Model For Square Wave Voltammetry At A Microelectrode, Patrick Enright, John Cassidy, Tony Betts Jan 2008

Evaluation Of A Naive Model For Square Wave Voltammetry At A Microelectrode, Patrick Enright, John Cassidy, Tony Betts

Articles

A square wave voltammetric waveform ( SWV) was applied to an inlaid microdisk electrode in a solution of K4[Fe(CN)6]. A simple model relying on the assumption of steady state current throughout the scan was used to model the current potential behaviour. However, experimental peak current magnitudes were between 30% and 50% greater than those predicted by the model. The model predicts an increase of peak current and peak width at half height with pulse height Esw and no effect of the parameters frequency, f and step height, ΔEs. Experimental peak current magnitudes and peak current magnitudes predicted by the model …


Improved High-Temperature Stability And Sun-Light-Driven Photocatalytic Activity Of Sulfur-Doped Anatase Tio2, Suresh Pillai, Declan Mccormack, Pradeepan Periyat, John Colreavy, Steve Hinder Jan 2008

Improved High-Temperature Stability And Sun-Light-Driven Photocatalytic Activity Of Sulfur-Doped Anatase Tio2, Suresh Pillai, Declan Mccormack, Pradeepan Periyat, John Colreavy, Steve Hinder

Articles

No abstract provided.


An Experiment Using A Simple Photoassisted Fuel Cell Designed To Remediate Simulated Wastewater, John Cassidy, Faisa Touati, Kevin Mcguigan Jan 2007

An Experiment Using A Simple Photoassisted Fuel Cell Designed To Remediate Simulated Wastewater, John Cassidy, Faisa Touati, Kevin Mcguigan

Articles

Work in photochemistry work peaked in the 1980’s where there was the prospect of using sunlight shining on suspensions of titanium dioxide in order to catalytically cleave water into hydrogen and oxygen [1-5]. In this way a clean and efficient method of producing hydrogen as a fuel was envisaged. However, there was a requirement to use a rather high energy light to achieve the splitting and it was not as efficient with visible light[5]. Doped TiO2 layers have been used in a three electrode system for formic acid degradation[6]. In this work, the system uses an electrode coated with TiO2 …


Improved Nitrate Sensing Using Ion Selective Electrodes Based On Urea–Calixarene Ionophores, Benjamin Schazmann, Dermot Diamond Jan 2007

Improved Nitrate Sensing Using Ion Selective Electrodes Based On Urea–Calixarene Ionophores, Benjamin Schazmann, Dermot Diamond

Articles

Urea–calix[4]arenes 1 and 2 were synthesised and incorporated into ISE membranes for assessment as sensors for inorganic anions in water. 1 revealed a strong response to all anions following the Hofmeister selectivity order. For ISEs of 2, the response to a portion of the anion series was suppressed, increasing the margin of selectivity of nitrate over chloride, a common interferant of nitrate in fresh and marine water samples. The performance of ISEs containing 2 was compared to commercially available alkylammonium nitrate ion-exchange salts used for nitrate sensing. Our ISEs performed favourably in terms of sensitivity, linear range and LOD performing …


A Chloride Selective Calix[4]Arene Optical Sensor Combining Urea Functionality With Pyrene Excimer Transduction, Benjamin Schazmann, Dermot Diamond Jan 2006

A Chloride Selective Calix[4]Arene Optical Sensor Combining Urea Functionality With Pyrene Excimer Transduction, Benjamin Schazmann, Dermot Diamond

Articles

A neutral 2-site chloride selective compound has been developed (3), based on a 1,3- alternate tetrasubstituted calix[4]arene providing a preorganised supramolecular scaffold. The resultant supramolecular cavity is amongst the first to combine urea functional groups bridged with single methylene spacers to pyrene moieties. It combines a naturally and synthetically proven H-bonding system with the elegant ratiometric fluorescent signalling properties of an intramolecular pyrene excimer system, triggered by conformational changes upon anion coordination. The excimer emission of 3 is quenched, with a simultaneous rise in the monomer emission solely by the chloride anion amongst a wide variety of anions tested. 3 …


Development Of A Calix[4]Arene Sensor For Soft Metals Based On Nitrile Functionality, Benjamin Schazmann, Dermot Diamond Jan 2006

Development Of A Calix[4]Arene Sensor For Soft Metals Based On Nitrile Functionality, Benjamin Schazmann, Dermot Diamond

Articles

The current work is amongst the first to examine the potential usefulness of the nitrile functional group in potentiometric analytical sensors for soft metals. Nitrile functionality has hereby been incorporated into a calix[4]arene skeleton to give a series of new cation selective hosts. The analytical sensing behaviour of these hosts was examined by Ion Selective Electrode (ISE) based potentiometry. In all cases a preference for soft metals was observed, explained primarily in terms of soft–soft compatibility between calix[4]arene nitrile hosts and metal guests in combination with a classical ‘lock and key’ best fit mechanism. Hosts 2, 3 and 4 showed …


Simulation Of Dynamic Electrochemical Processes, John Cassidy Jan 2003

Simulation Of Dynamic Electrochemical Processes, John Cassidy

Articles

This work is designed to introduce electrochemists in a tutorial manner to the basics of modeling of electrochemical systems based primarily on diffusion equations. There is an introduction to analytical and numerical methods with examples taken from typical electrochemical experiments. The Laplace transform is used to derive the Cottrell equation and chronopotentiometry. The response of an electrode to a Gaussian concentration profile is detailed. Laplace’s equation is solved for a simple cell to determine the potential distribution. Discrete methods are employed to calculate the current time behavior following a potential step using the explicit finite difference method. Cyclic voltammetry is …