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Douman SF, De Eguilaz MR, Cumba LR, Beirne S, Wallace GG, Yue Z, Iwuoha EI, Forster RJ. Electrochemiluminescence at 3D Printed Titanium Electrodes. Front Chem 2021; 9:662810. [PMID: 34113601 PMCID: PMC8186460 DOI: 10.3389/fchem.2021.662810] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 04/06/2021] [Indexed: 11/13/2022] Open
Abstract
The fabrication and electrochemical properties of a 3D printed titanium electrode array are described. The array comprises 25 round cylinders (0.015 cm radius, 0.3 cm high) that are evenly separated on a 0.48 × 0.48 cm square porous base (total geometric area of 1.32 cm2). The electrochemically active surface area consists of fused titanium particles and exhibits a large roughness factor ≈17. In acidic, oxygenated solution, the available potential window is from ~-0.3 to +1.2 V. The voltammetric response of ferrocyanide is quasi-reversible arising from slow heterogeneous electron transfer due to the presence of a native/oxidatively formed oxide. Unlike other metal electrodes, both [Ru(bpy)3]1+ and [Ru(bpy)3]3+ can be created in aqueous solutions which enables electrochemiluminescence to be generated by an annihilation mechanism. Depositing a thin gold layer significantly increases the standard heterogeneous electron transfer rate constant, ko, by a factor of ~80 to a value of 8.0 ± 0.4 × 10−3 cm s−1 and the voltammetry of ferrocyanide becomes reversible. The titanium and gold coated arrays generate electrochemiluminescence using tri-propyl amine as a co-reactant. However, the intensity of the gold-coated array is between 30 (high scan rate) and 100-fold (slow scan rates) higher at the gold coated arrays. Moreover, while the voltammetry of the luminophore is dominated by semi-infinite linear diffusion, the ECL response is significantly influenced by radial diffusion to the individual microcylinders of the array.
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Affiliation(s)
- Samantha F Douman
- National Centre for Sensor Research, Chemistry Department, Dublin City University, Dublin, Ireland.,SensorLab (University of the Western Cape Sensor Laboratories), University of Western Cape, Cape Town, South Africa
| | - Miren Ruiz De Eguilaz
- National Centre for Sensor Research, Chemistry Department, Dublin City University, Dublin, Ireland
| | - Loanda R Cumba
- National Centre for Sensor Research, Chemistry Department, Dublin City University, Dublin, Ireland
| | - Stephen Beirne
- Australian Research Council, Centre of Excellence for Electromaterials Science, Intelligent Polymer Research Institute, University of Wollongong, Wollongong, NSW, Australia
| | - Gordon G Wallace
- Australian Research Council, Centre of Excellence for Electromaterials Science, Intelligent Polymer Research Institute, University of Wollongong, Wollongong, NSW, Australia
| | - Zhilian Yue
- Australian Research Council, Centre of Excellence for Electromaterials Science, Intelligent Polymer Research Institute, University of Wollongong, Wollongong, NSW, Australia
| | - Emmanuel I Iwuoha
- SensorLab (University of the Western Cape Sensor Laboratories), University of Western Cape, Cape Town, South Africa
| | - Robert J Forster
- National Centre for Sensor Research, Chemistry Department, Dublin City University, Dublin, Ireland.,FutureNeuro SFI Research Centre, Dublin, Ireland
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