Electrochemically hybrid films

Yu, A., et al., Silver nanoparticle-carbon nanotube hybrid films Preparation and electrochemical sensing. Electrochimica Acta, 2012. 74(0) p. 111-116. 

Xue, M. H., Xu, Q., Zhou, M. and Zhu, J. J. (2006), In situ immobilization of glucose oxidase in chitosan-gold nanoparticle hybrid film on prussian blue modified electrode for high-sensitivity glucose detection. Electrochem. Commun., 8(9) 1468-1474. 

Pauporte, T., Yoshida, T., Cortes, R., Froment, M., and Uncot, D. (2003) Electrochemical growth of epitaxial eosin/ZnO hybrid films. /. Phys. Chem. B, 107,10077-10082. 

L.M. (2004) Electron transport and back reaction in electrochemically self-assembled nanoporous ZnO/dye hybrid films. J. Phys. Chem. B, 108, 8364-8370. 

Lang, X., Zhang, L., Fujita, T., Ding, Y, Chen, M., 2012. Three-dimensional bicontinuous nanoporous Au/ polyaniline hybrid films for high-performance electrochemical supercapacitors. J. Power Sources 197, 325-329. 

Figure 4 (A) AFM images (a) MWNTs/CoTMPyP/RCI film assembled on GC electrode (before electrochemical reduction) (b) MWNTs/CoTMPyP/R hybrid film (after electrochemical reduction at - 0.7 V in N2-saturated 0.1 mol I KCI solution). (B) XPS data of MWNTs/CoTMPyP film on GC surface (cun/es (a) and (b)) and MWNTs/CoTMPyP/RCii" film in the R (4f) region before (cun/e (c)) and after (cun/e (d)) electrochemical reduction. (Qu JY, Shen Y, Qu XH, and Dong SJ (2004) Preparation of hybrid thin film modified carbon nanotubes on glassy carbon electrode and its electrocatalysis for oxygen reduction. Chemical Communications 2004 34-35 reproduced by permission of The Royal Society of Chemistry.)...

Huang D, Lu J, li S, Luo Y, Zhao C, Hu B, Wang M, Shen Y. Fabrication of cobalt porphyrin. Electrochemically reduced graphene oxide hybrid films for electrocatalytic hydrogen evolution in aqueous solution. Langmuir 2014 30 6990-8. 

Additionally, a hybrid thin-film electrode of CNTs containing Pt nanoparticles and [tetrakis(A-methylpyridyl)porphyrinato]cobalt (CoTMPyP) was fabricated by Qu et al. [88]. At first a PtCl layer was absorbed on flic surface of the CoTMPyP-modified nanotube electrode through electrostatic interaction. This layer was then reduced electrochemically to yield Pt nanoparticles under constant potential at -0.7 V. They found that the hybrid film electrode exhibited high electrocatalytic activity for oxygen reduction to produce H2O through a four electron pathway reduction with high stability. 

Shen Y, Zhan F, Lu J, Zhang B, Huang D, Xu X, Zhang Y, Wang M (2013) Preparation of hybrid films containing gold nanoparticles and cobalt porphyrin with flexible electrochemical properties. Thin Solid Films 545 327-331... 

We are yet to fiilly understand the mechanism by which these multifunctional inhibitors protect the surface however, it appears from the electrochemical and surface characterization evidence for both steel and aluminium alloys that a hybrid film forms in each case. The following summarizes our current understanding of the formation of this surface ... 

Vila, N., Ghanbaja, J., Aubert, E., and Walcarius, A. (2014) Electrochemically assisted generation of highly ordered azide-functionalized mesoporous silica for oriented hybrid films. Angew. Chem., Int Ed., 53 (11), 2945 2950. 

The electrochemical deposition of sol-gel hybrid films was carried out in a mixture of at least two different sol-gel precursors. For example, Walcarius and coworkers [19-21,45] reported the co-electrodeposition of TEOS or methyltrie-thoxysilane (MTES) together with APTES or MPTMS for the electroanalysis of Cu(II) and Hg(II) in aqueous media. Liu and Mandler [46] reported the coelectrodeposition of TMOS with Ti(i-OPr)4, where they found that the obtained films had graded structure in composition. These works will be discussed in detail in this section. 

Unlike the co-electrodeposition of different metals, cross-linking between different precursors makes it impossible to fidly separate the deposition of different components by adjusting electrochemical parameters such as potential. The kinetics of the co-electrodeposition process is very comphcated, although the ratio between different sol-gel precursors could be altered in a hmited range by changing deposition conditions. The manipulation of the deposition process for preparing sol-gel hybrid films remains a challenge. 

Sun, L.-J., et al., Electrodeposited hybrid films of polyaniline and manganese oxide in nanofibrous structures for electrochemical supercapacitor. Electrochim. Acta, 2008. 53 p. 3036-3042. 

The anticorrosion performance of these coatings assessed by electrochemical impedance spectroscopy shows that the lower impedance was obtained when BTA was directly added to the sol-gel matrix, whereas the best performance was achieved with inhibitor-doped TiO coated with a hybrid film. In terms of active corrosion protection, there is a periodic decrease/increase of impedance associated with the breakdown followed by the self-healing of the intermediate oxide layer. SVET was employed to study the self-healing ability of bi-layer systems at the micro level. The measurements of local corrosion current evolution in the zones of artificial defects have demonstrated well-defined corrosion activity on the sirrface of AA2024 coated with sol-gel film only, while no corrosion activity was revealed even after 24 hours on the alloy treated with a bi-layer system. The reported resirlts show that the adsorbed inhibitor is leached out from the porous... 

Chitosan-Pmssian blue-multiwall carbon nanotube-hollow gold nanosphere (Chit-PB-MWNT-HGN) films were fabricated to be employed in AChE biosensorsIncorporating MWNTs and HGNs into a Chit-PB hybrid film promoted the electron transfer reaction, enhanced the electrochemical response, and improved the microarchitecture of the electrode surface. Based on the inhibition of the AChE activity by the pesticides malathion, chlorpyrifos, monocrotophos, and carbofuran as model compounds, the biosensor showed a wide dynamic range, low detection limit, good reproducibility, and high stability. Moreover, the AChE/Chit-PB-MWNT-HGN/Au biosensor could also be used for the direct analysis of a practical samples, which would be a new promising tool for pesticide analysis. 

For application of protein-immobilized porous materials to sensor fields, use of an electroactive substance as the framework material is important. DeLouise and Miller demonstrated the immobilization of glutathione-S-transferase in electrochemically etched porous silicon films [134], which are attractive materials for the construction of biosensors and may also have utility for the production of immobilized enzyme bioreactors. Not limited to this case, practical applications of nanohybrids from biomolecules and mesoporous materials have been paid much attention. Examples of the application of such hybrids are summarized in a later section of this chapter. 

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