Sol–Gel Route to Zirconia–Pt-Nanoelectrode Arrays 8 nm in Radius: Their Geometrical Impact in Mass Transport

Abstract

The fabrication of advanced nanoelectrode arrays and their electrochemical characterization are presented. These nanoelectrode arrays are constituted of nanoperforations of 8 nm in radius leading to platinum and protected by an inorganic matrix made of crystalline zirconia. These nanoelectrodes arrays provide a ceramic support with a high thermal and chemical stability. These devices present a well characterized structure with a control of size, shape, and spacing of the nanoelectrodes, allowing studying in depth both the mass transport and the charge transfer properties in the nanometer range. The radial diffusion occurs when the experimental scan rate is superior to a theoretical scan rate estimated from the model proposed by Amatore and colleagues. The coupling between electrochemical analysis and nanoscale structural characterizations successfully demonstrates that the theory defined for microelectrode arrays can be directly transposed for well-defined metal-ceramic nanocomposite nanoelectrodes.

Mesoporous materials and electrochemistry

“…12B. Effects of porosity and pore orientation were also reported for mesoporous titania 282 or zirconia 283 films (see Fig. 12C for an illustration of permeability through zirconia films templated at various extents).…”

Molecular Transport through TiO2 Mesoporous Thin Films: Correlation with the Partially Blocked Electrode Model

“…The case of MTTF electrodes may be then understood as a particular condition of the partially blocked electrode model, , where the electroactive zones (i.e., open pores) are tightly packed and are much smaller than the diffusion layer length. As a consequence, a linear diffusion profile is generated and the sample behaves as a planar electrode, even when a large fraction of the electrode surface is covered by an insulating material, in this case, TiO 2 . , A first approach to apply this concept to mesoporous films was presented by Fontaine et al using ZrO 2 ultrathin films . Moreover, this similar response between bare ITO and mesoporous thin film-covered ITOs has been observed, but not discussed, in the literature …”

“…The latter analysis requires a number of assumptions that are not always realistic, such as the existence of planar diffusion profiles around the sample surface or the proportionality between the measured current and a geometrical factor referred to the uncovered electrode . Some other studies were performed on ZrO 2 ultrathin mesoporous films to minimize the effect of thickness but were also strongly supported on additional electrochemical techniques such as electrochemical impedance spectroscopy. , Hence, a detailed study of the voltammograms obtained for MTTFs is still missing, as well as their proper interpretation using a more adequate model that profits from not only peak current but also voltammogram shapes.…”

Self-assembled inorganic nanopatterns (INPs) made by sol-gel dip-coating: Applications in nanotechnology and nanofabrication

“…The cyclic voltammetry and galvanostatic investigations revealed that these NEAs exhibit characteristic overlapped regimes of diffusion associated with enhanced red/ox probe sensitivity (see Fig. 14) [29,30]. These INP NEA surfaces were then modified by growing polymers (poly(-phenylene)oxide) by anodic electro-polymerisation at the bottom of the discrete gold nanodisk electrodes or by attaching a functional group ((CF 3 e(CF 2 ) 2 e(CH 2 ) 5 O) 2 POO e ) locally to the continuous ceramic network [28].…”