Electrode arrays

A compound which is a good choice for an artificial electron relay is one which can reach the reduced FADH2 active site, undergo fast electron transfer, and then transport the electrons to the electrodes as rapidly as possible. Electron-transport rate studies have been done for an enzyme electrode for glucose (G) using interdigitated array electrodes (41). The following mechanism for redox reactions in osmium polymer—GOD biosensor films has... 

The redox processes responsible for the switching of the bridging redox polymer can also be brought about by redox processes induced by molecular species in solution Alternatively, the switching processes can be designed so that a solution component is essential for, or mediates the redox process. The array electrode can then be used as a sensor for those solution constituents. 

J.H. Thomas, S.K. Kim, P.J. Hesketh, H.B. Halsall, and W.R. Heineman, Microbead-based electrochemical immunoassay with interdigitated array electrodes. Anal. Biochem. 328,113-122 (2004). 

H.S. Jung, J.M. Kim, J.W. Park, H.Y. Lee, and T. Kawai, Amperometric immunosensor for direct detection based upon functional lipid vesicles immobilized on nanowell array electrode. Langmuir 21, 6025-6029 (2005). 

M. Hartmann, E.W. Grabner, and P. Bergveld, Prussian blue-coated inter-digitated array electrodes for possible analytical application. Anal. Chim, Acta 242, 249—257 (1991). 

Yang, W. C., Yu, A. M., and Chen, H. Y. (2001). Applications of a copper microparticle-modified carbon fiber microdisk array electrode for the simultaneous determination of aminoglycoside antibiotics by capillary electrophoresis. /. Chromatogr. A 905, 309—318. 

The results by Madou et al. are especially significant, as they clearly demonstrate the ability to fabricate array electrodes with aspect ratios that are on the order of 20 1. At these aspect ratios, the analytical models indicate that the capacity of 3-D batteries exceeds that of 2-D geometries. Two key questions remain to be answered for C-MEMS are these electrodes electrochemically reversible to lithium, and what is the resistance of rods with such high aspect ratios ... 

Fig. 5.22 Top surface FESEM view of the prepared CdS-Ti02 nanotube-array electrode after CdS electrodeposition at -0.5V for 30 minutes.

Fig. 5.37 Normalized visible reflectance spectra of CdS-Ti02 nanotube-array electrodes. ( 0 Ti02 nanotube-array electrode (b) 20 minute -0.5 V electro-deposited CdS modified Ti02 nanotube-array electrode, as fabricated (c) electrode of (b) after annealing at 350°C for 60 minutes in...

Figure 5.38 illustrates the experimental setup for water photoelectrolysis measurements with the nanotuhe arrays used as the photoanodes from which oxygen is evolved. The 1-V characteristics of 400 nm long short titania nanotuhe array electrodes, photocurrent density vs. potential, measured in IM KOH electrolyte as a function of anodization hath temperature under UV (320-400 nm, lOOmW/cm ) illumination are shown in Fig. 5.39. The samples were fabricated using a HF electrolyte. At 1.5V the photocurrent density of the 5°C anodized sample is more than three times the value for the sample anodized at 50°C. The lower anodization temperature also increases the slope of the photocurrent—potential characteristic. On seeing the photoresponse of a 10 V 5°C anodized sample to monochromatic 337 nm 2.7 mW/cm illumination, it was found that at high anodic polarization, greater than IV, the quantum efficiency is larger than 90%.

Fig. 5.49 Photocurrent versus voltage in 1 M NazS under AM 1.5 (1 sun), lOOmW/cm illumination (jO bare Ti02 nanotube electrode. (b) As-prepared electrodeposited CdS film (-0.5 V, 30 min.) upon TiOz nanotube-array electrode, (c) CdS (-0.5 V, 30 min.)-Ti02 electrode after annealing at 350°C in N2 for 60 minutes, (d) CdS (-0.5 V, 30 min.)-Ti02 electrode after annealing at 400°C in N2 for 60 minutes.

Paulose M, Shankar K, Varghese OK, Mor GK, Hardin B, Grimes CA (2006) Backside illuminated dye-sensitized solar cells based on titania nanotube array electrodes. Nanotechnol 17 1446-1448... 

In Ref 13, a new approach toward the preparation of Au(lll) nanoisland-arrayed electrode based on fine colloidal nanolayer-directed seeding growth has been presented. 

Recently, arrayed electrodes, which consist of several ultramicroelectrodes of the same type or of different types are prepared and used in sophisticated ways [8h],... 

B.J. Feldman and R.W. Murray, Electron diffusion in wet and dry Prussian blue films on interdigitated array electrodes, Inorg. Chem., 26 (1987) 1702-1708. 

Actually, there are reports on transforming the negative effect of separation electric field into new detection approaches. A potentiostat-less detection scheme for amperometric detection in CE based on the use of microband array electrodes situated in the CE electric field has been proposed [53] as well as the use of an indirect amperometric detection with a carbon fibre in-channel configuration [54]. In this case, the potential difference induced by the CE separation electric field produces a change in the reduction potential of oxygen, which can be used to determine nonelectroactive analytes. 

Mixer type Electrical dot-array Electrode unit in the 3x3... 

Using chip-array electrodes even trace metals can be detected with high selectivity [60]. 

Figure 5.1.9 PEC solar cell. Bottom scheme of the cell with electron microscopy images of a particular of the Ti02-nanotube array electrode and of the Fe nanoparticles on N-doped carbon nanotubes, used as a photocatalyst for water oxidation and an electrocatalyst for CO2 reduction, respectively. It is also shown that it may be possible to use this cell for the production of H2/O2 in separate compartments by water photoelectrolysis. Top photo of the experimental cell and of the assembly of the photoanode with the Nafion membrane. Adapted from [14, 40, 52],...

Each of the electrode geometries shown in Fig. 1 can be arranged in groups to form array electrodes, examples of which are shown in Fig. 2. The behavior of array electrodes depends on the ratio of the diameter of the individual electrode features to the spacing between electrode features as demonstrated in Fig. 3. Arrays may be made using lithographic procedures or electrochemical or electroless template deposition methods. 

Construction of Nano-Array Electrode Material for Amperometric Detection... 

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