Dr Debbie Silvester

Qualifications

MSc (Bristol), DPhil (Oxon)

Biography

2009-present: Targeted Research Fellow, Curtin University, Perth, WA, Australia
2005-2008: DPhil (PhD) on ‘Electrochemical Studies in Room Temperature Ionic Liquids’ with Prof. Richard G. Compton, University of Oxford, UK
2001-2005: MSci with a year in North America at University of Bristol, UK. (Research project with Dr. Jason Riley and Prof. Andrew Orr-Ewing)
2003-2004: Study abroad year at the University of North Carolina at Chapel Hill, NC, USA. (Research project with Prof. Royce W. Murray)

Fields of Interest

Electrochemistry, room temperature ionic liquids (RTILs), sensing, conducting polymers, liquid|liquid interface.

Research Activities

Debbie Silvester’s research activities include understanding electrochemical processes with a focus on sensing. She is particularly interested in the role of room temperature ionic liquids (RTILs) as replacements for organic solvents in various electrochemical reactions. RTILs are a new and interesting class of solvent that possess several properties such as: negligible vapour pressure, intrinsic conductivity, wide electrochemical windows, high chemical and thermal stability, high polarity and the ability to dissolve a wide range of compounds. Current interests include:

1. Electrochemical sensing of toxic gases in RTILs. Most conventional solvents employed as electrolytes in gas sensors cannot survive drastic pressure and temperature changes that can be encountered in harsh environments. As a result, the electrolyte can quickly dry up and the lifetime of a sensor is very limited (e.g. must be replaced every 2-3 weeks). The low vapour pressure and high thermal stability of RTILs makes them ideal candidates as electrolytes in highly robust gas sensors with a long working lifetime in harsh environments. In this work, the electrochemical reactions and mechanisms of various toxic gases and unexplored materials in RTILs will be studied and the sensitivity and selectivity towards a certain gas will be determined. This work will be initially investigated by Krishnan S/O Murugappan, an Honours student in 2011.
2. Ion sensing at water|RTIL interfaces. Electrochemistry at the liquid|liquid interface offers the possibility to detect ions that are cannot be detected at conventional solid|liquid interfaces (i.e. are not redox active). Conventional liquid|liquid ion sensing employs a water phase in contact with an immiscible organic solvent such as 1,2-dichloroethane or nitrobenzene. Recently, hydrophobic RTILs have also been explored at the liquid|liquid interface. A range of ionic liquids with different anions and cations will be explored as solvents, and various analyte ions will be transferred across the interface. The work will begin with ion-sensing at micro-array interfaces fabricated on a silicon wafer. We will explore the possibility of replacing conventional solvents with non-volatile RTILs in robust electrochemical ion sensors. This work is in collaboration with A/Prof Damien Arrigan at Curtin.
3. Conducting polymer deposition in ionic liquids and their use in solid-contact ion-selective electrodes (SC-ISEs). SC-ISEs consist of an inert metal substrate (usually gold or platinum) coated with an electroactive conducting polymer that can be doped with ions. Conducting polymers are typically deposited onto the metal substrate of SC-ISEs by electropolymerization in a solvent in which the monomer is soluble. The charge is normally controlled to give a certain thickness of the polymer, but the smoothness/porosity of the film is dependent on the characteristics of the individual polymer. Many polymers are highly porous, which is not so favourable for sensor applications. Recently, it has been found that polymer films deposited in ionic liquids are much denser and smoother than those deposited in conventional media. This project will focus on conducting polymer deposition in ionic liquids and their applications in SC-ISEs for environmental monitoring. This work is in collaboration with Dr. Manzar Sohail at Curtin/Uni. Sunshine Coast.

Selected publications

Debbie has authored and co-authored over 30 publications in peer-reviewed international journals. Listed below are some selected publications in the last 5 years:

• Silvester, D. S.; Grygolowicz-Pawlak, E.; Bakker, E. Potentiometric determination of coextraction constants of potassium salts in ion-selective electrodes utilizing a nitrobenzene liquid membrane phase Anal. Chim. Acta (2010), 683, 92-95.
• Silvester, D. S.; Grygolowicz-Pawlak, E.; Bakker, E. Assessing Ion-Exchanger Properties and Purity of Lipophilic Electrolytes by Potentiometry and Spectrophotometry Electrochem. Commun. (2010), 12(1), 110-113.
• Barrosse-Antle, L. E.; Bond, A. M.; Compton, R. G.; O’Mahony, A. M.; Rogers, E. I.; Silvester, D. S. Voltammetry in room temperature ionic liquids: Comparisons and contrasts with conventional electrochemical solvents Chem. Asian J. (2010), 5(2), 202-230.
• Silvester, D. S.; Rogers, E. I.; Barrosse-Antle, L. E.; Broder, T. L.; Compton, R. G. The electrochemistry of simple inorganic molecules in room temperature ionic liquids. J. Braz. Chem. Soc. (2008), 19, 611-620.
• O’Mahony, A. M.; Silvester, D. S.; Aldous, L.; Hardacre, C.; Compton, R. G. Effect of water on the electrochemical window and potential limits of room temperature ionic liquids J. Chem. Eng. Data (2008), 53(12), 2884-2891.
• Rogers, E. I.; Silvester, D. S.; Poole, D. L.; Aldous, L.; Hardacre, C.; Compton, R. G. Voltammetric characterisation of the ferrocene|ferrocenium and cobaltocenium|cobaltocene redox couples in RTILs. J. Phys. Chem. C (2008), 112(16), 6551-6557.
• Silvester, D. S.; Broder, T. L.; Aldous, L.; Hardacre, C.; Crossley, A.; Compton, R. G. Using XPS to determine solute solubility in room temperature ionic liquids. Analyst (2007), 132(3), 196-198.
• Silvester, D. S.; Aldous, L.; Hardacre, C.; Compton, R. G. An Electrochemical Study of the Oxidation of Hydrogen at Platinum Electrodes in Several Room Temperature Ionic Liquids. J. Phys. Chem. B (2007), 111(18), 5000-5007.
• Silvester, D. S.; Compton, R. G. Electrochemistry in room temperature ionic liquids: a review and some possible applications. Z. Phys. Chem. (2006), 220(10-11), 1247-1274.
• Cheng, P. P. H.; Silvester, D.; Wang, G.; Kalyuzhny, G.; Douglas, A.; Murray, R. W. Dynamic and Static Quenching of Fluorescence by 1-4 nm Diameter Gold Monolayer-Protected Clusters. J. Phys. Chem. B (2006), 110(10), 4637-4644.

Book chapter

• Silvester, D. S.; Rogers, E. I.; Compton, R. G. Reference Electrodes for use in RTILs. Chapter 13.2 in the book“Electrodeposition from Ionic Liquids” Eds. Endres, F.; MacFarlane, D.; Abbot, A.; 2008.

Selected Conference presentations

• February 2011: Seminar at the ACES Electromaterials Symposium, Innovation Campus, Wollongong, NSW, Australia,
• July 2010: Poster presentation at the 13th International Meeting on Chemical Sensors (IMCS), University of Western Australia, Perth, WA, Australia.
• June 2009: Poster presentation at the 3rd Conference on Ionic Liquids (COIL-3) in Cairns, QLD, Australia.
• May 2007: Poster presentation entitled “Electrochemistry of nitrogen and phosphorus compounds in room temperature ionic liquids” at the 90th Canadian Chemistry Conference in Winnipeg, Canada
• April 2007: Mini-plenary lecture entitled “Voltammetry of reactive phosphorus compounds in room temperature ionic liquids: PCl₃ and POCl₃” at the XVI Simpósio Brasileiro de Electroquímica e Eletroanalítica, Sao Paulo, Brazil

Contact

The sensors group at Curtin (headed by Damien Arrigan and Debbie Silvester) is rapidly expanding and we are always interested in hearing from anyone who is interested in joining our group. Please contact d.arrigan@curtin.edu.au or D.Silvester-Dean@curtin.edu.au to discuss possibilities.