Development of cerium oxide based electrochemical sensors for detection of environmental pollutants

Usage of inorganic materials for the development of organic electrodes with well-defined morphology and physicochemical properties is a promising route for the construction of novel sensing devices for monitoring of the environmental pollutants. Among other materials, cerium dioxide became attractive because of its specific electronic properties and successful applications in catalytic and healthcare systems. Recently, we showed that cerium oxide thin films can be used as an enzyme-free electrode material for electrochemical detection and quantification of hydrogen peroxide (DOI: 10.1016/j.apsusc.2019.05.205). In general, research on application of an inorganic material for sensing and detection of organic molecules is an extremely complex task and is often based on empirical observations. Model studies at various levels of complexity are expected to better understand the role of electrode material for sensing applications.

Herein, we propose to study and develop an electrochemical model sensor based on cerium oxide film for the detection of commonly used herbicides in agriculture, i.e. glyphosate, glufosinate, bialaphos molecules, etc. Efforts are definitively needed in developing sensitive and selective analytical methods for the implementation of proper technologies for the on line and real time monitoring of herbicides and their remediation in contaminated areas.

Following a bottom-up approach, we propose to combine electrochemical techniques (often used for sensing system development) coupled with surface science techniques to assess activity of cerium oxide electrodes versus herbicide molecules.

Electrochemical measurements will be performed using cyclic voltammetry, chronoamperometry and electrochemiluminescence methods to determine sensitivity, detection limits and linearity of the sensing system. This part will be carried out in close cooperation with Dr. Alessandra Zanut from the Department of Chemical Science, University of Padova, Italy, which has extensive expertise in the electrochemical techniques mentioned above and their application in sensing devices. The electrode surface analysis will be performed by synchrotron radiation based techniques (SRPES, RPES, NEXAFS, etc.) at the Materials Science Beamline of Elettra Sincrotrone, Trieste.

The study will benefit from the classic surface science approach that gives insight on electronic structure changes of the surface that may be responsible for sensor sensitivity. In addition, we will use a robust, reproducible, and affordable technique for preparation of cerium electrodes which has been already developed in our department for potential sensing devices. Based on the results obtained, exploratory experiments will be carried out to determine whether the performance of the sensors (detection limit, linearity, stability) can be improved by changing the morphology of the oxide films.

This project is expected to favour the formation of young researchers and to strengthen ongoing collaborations between Charles University and University of Padova. High-value data and knowledge will be exchanged among universities to optimize the research results and reach important milestones in the use of cerium oxide films for sensing and green technologies.

Literature

1. Surface Analysis by Auger and X-Ray Photoelectron Spectroscopy, D. Briggs, J. T. Grant, IMPublications, Chichester, UK and SurfaceSpectra, Manchester, UK, 2003, ISBN: 1‐901019‐04‐7.
2. Catalysis by Ceria and Related Materials, A. Trovarelli, Imperial College Press, London, UK, 2002, ISBN: 978-1-86094-299-0.
3. Electrochemical Methods: Fundamentals and Applications, 3rd Edition, by A. J. Bard, L. R. Faulkner, H. S. White, Willey, 2022, ISBN-13: 978-1119334064