Electrochemiluminescence at 3D Printed Titanium Electrodes
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Date
2021
Journal Title
Journal ISSN
Volume Title
Publisher
Frontiers Media SA
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.
Description
Keywords
Heterogeneous electron transfer kinetic, Annihilation and co-reactant system, Voltammetry, 3D-electrode array, Electrochemiluminescence
Citation
Douman SF, De Eguilaz MR, Cumba LR, Beirne S, Wallace GG, Yue Z, Iwuoha EI and Forster RJ (2021) Electrochemiluminescence at 3D Printed Titanium Electrodes. Front. Chem. 9:662810. doi: 10.3389/fchem.2021.662810