Nanoparticles electrochemical properties

Electrodeposition of metals can be performed under different electrochemical modes. In the work mentioned in Ref. [18], it was performed in potentiostatic mode. The potential value for formation of platinum nanoparticles is —25 mV vs. SCE the deposition is performed from 2.5 mM solution of H2[PtCl6] in 50 mM KCl. The size of nanoparticles formed depends on the reduction charge. Continuous monitoring of the charge in potentiostatic mode is provided by different potentiostats, for example, by Autolab-PG-stat (EcoChemie, The Netherlands). Conditions for deposition of other metals should be selected according to their electrochemical properties. 

The mass activity MA (in A g ) of the Pt catalyst is, of course, the product of the specific activity js (in A m ) and the specitic surface area 5mass (in ni g ) MA = js mass- Because S ass is inversely proportional to the particle diameter dpt, the use of supported Pt nanoparticles is effective for increasing MA, if js is a constant independent of dpt- However, even at pure Pt, conflicting results on the values of js and P(H202) have been reported, suggesting the presence of differences in electrochemical properties between bulk and supported nanoparticles. For example, Bregoli [1978]... 

Inaba M, Ando M, Hatanaka A, Nomoto A, Matsuzawa K, Tasaka A, Kinumoto T, Iriyama Y, Ogumi Z. 2006. Controlled growth and shape formation of platinum nanoparticles and their electrochemical properties. Electrochim Acta 52 1632-1638. 

A. Salimi, E. Sharifi, A. Noorbakhsh, and S. Soltanian. Direct voltammetry and electrocatalytic properties of haemoglobin immobilized on a glassy carbon electrode modified with nickel oxide nanoparticles. Electrochem. Commun. 8, 1499-1508 (2005). 

Wang E, Cheng W, Dong S (2002) Gold nanoparticles As Fine Tuners of Electrochemical Properties of Electrode/Solution Interface. Langmuir 18(25) 9947-9952... 

In a similar way, the emergence of nanoparticles having optical and/or electrochemical properties has led to the achievement of new labels for DNA chips. These labels, which have nanometer size, require nucleic acid grafting procedures similar to those performed on a flat surface or on micrometer size beads. 

The electrochemical properties of Ir02 and RUO2 nanoparticles, deposited on synthetic boron-doped diamond (BDD) surfaces, are discussed. After a description of the preparation procedure and the morphological characterization of BDD/Ir02 and BDD/RUO2 samples, the dispersion efficiency of these oxides on BDD was estimated for different loading, using cyclic voltammetry. 

Most of the electrochemical phenomena occur in size regimes that are very small. The effects of size on diffusion kinetics, electrical double layer at the interface, elementary act of charge transfer and phase formation have recently been reviewed by Petrri and Tsirlina [12]. Mulvaney has given an excellent account of the double layers, optical and electrochemical properties associated with metal colloids [11]. Special emphasis has been given to the stability and charge transfer phenomenon in metal colloid systems. Willner has reviewed the area of nanoparticle-based functionalization of surfaces and their applications [6-8]. This chapter is devoted to electrochemistry with nanoparticles. One of the essential requirements for electrochemical studies is that the material should exhibit good conductivity. 

In this chapter, we review the recent progress in the development of different metal oxide nanoparticles with various shapes and size for fabrication of biosensors. The development of metal oxide nanomaterials surface film for direct electron exchange between electrodes and redox enzymes and proteins will be summarizing. The electrochemical properties, stability and biocatalytic activity of the proposed biosensors will be discussed. The biocompatibility of the metal oxide nanomaterials for enzymes and biomolecules will be evaluated. We will briefly describe some techniques for the investigation of proteins and enzymes when adsorbed to the electrode surfaces. Cyclic voltammetry, impedance spectroscopy, UV-visible spectroscopy and surface imaging techniques were used for surface characterization and bioactivity measuring. 

Figure 33. (A) CV response of GC electrode modified with CoOx Nanoparticles in pH 12 solutions at v = 20 mVs 1 (B) SEM image of the electrodeposited CoOx on GC electrode. Reprinted from Analytica Chimica Acta, 594, A. Salimi, R. Hallaj, H. Mamkhezri, S. Soltanian, Nanomolar detection of hydrogen peroxide on glassy carbon electrode modified with electrodeposited cobalt oxide nanoparticles,26,Copyrights(2007) and J. Electroanalytical Chemistry, 619-620, A. Salimi, R.Hallaj, H. MamKhezri, S.M.T. Hosaini, Electrochemical properties and electrocatalytic activity of FAD immobilized onto cobalt oxide nanoparticles Application to nitrite detection,33, Copyrights (2008) with permission from Elsevier.

AuNPs in Liquid-State Environment Solute pure and monolayer-coated ( capped ) AuNPs are central targets in colloid and surface science also with a historical dimension [258-262]. Facile chemical syntheses introduced by Schmid et al. [260] and by Brust et al. [263] have boosted AuNP and other metal nanoparticle science towards characterization of the physical properties and use of these nanoscale metallic entities by multifarious techniques and in a variety of environments. Physical properties in focus have been the surface plasmon optical extinction band [264—269], scanning and transmission electron microscopy properties, and electrochemical properties of surface-immobilized coated AuNPs [173, 268-276], To this can be added a variety of AuNP crosslinked molecular and biomolecular... 

Bulk nanostructured materials are soUds with nanosized microstructure. Their basic units are usually nanoparticles. Several properties of nanoparticles are useful for applications in electrochemical sensors [67], However, their catalytic behavior is one of the most important. The high ratio of surface atoms with free valences to the total atoms has led to the catalytic activity of nanostructured SEs being used in electrochemical reactions. The catalytic properties of nanoparticles could decrease the overpotential of electrochemical reactions and even provide reversibility of redox reactions, which are irreversible at the bulk metal SE [68], Multilayers of conductive nanoparticles assembled on electrode surfaces produce a high porous surface with a controlled microenviromnent. These structures could be thought of as assemblies of nanoelectrodes with controllable areas. 

As for PPy s, there has been an explosion of interest in the synthesis of PAn s with nanodimensions, as such materials have been shown to have enhanced electronic and electrochemical properties. Formation of PAn nanoparticles has been achieved via polymerization in micelles, using either sodium dodecyl sulfate (SDS)211 or DBSA212 214 as the surfactant stabilizer. Particle sizes in the range of 10-30 nm with conductivities as high as 24 S cm-1 have been reported. 

Recently, sol-gel processes became a technique for the preparation of NS-Ti02. It has been demonstrated that through sol-gel processes, the physico-chemical and electrochemical properties of Ti02 can be modified to improve its efficiency. It provides a simple and easy means of synthesizing nanoparticles at ambient temperature under atmospheric pressure and this technique does not require complicated set-up. Since this method is a solution process, it has all the advantages over other preparation techniques in terms of purity, homogeneity, control of... 

Other uses of nanostructured chromophores may include fluorescent nanoparticles or nanoparticle-based porous materials that change their light absorption or emission when a toxin is encountered. Some metal oxides and POMs already exhibit such properties. Likewise, electrochemical properties, including induced photocurrents, could be sensitive to encountering a toxin. Clearly, both decontamination and detection are relevant aspects here. Basic research is needed on the design and synthesis of engineered nanostructures whose electronic structures, thermal catalytic, photophysical (emission), and photocatalytic properties are strongly perturbed by the presence or absence of toxic compounds. 

S. Tian, J. liu, T. Zhu, and W. KnoU, Polyaniline doped with modified gold nanoparticles and its electrochemical properties in neutral aqueous solution, Chem. Commun., 2738 739 (2003). 

Nithya, V. D., R. K. Selvan, D. Kalpana, L. Vasylechko, and C. Sanjeeviraja. 2013. Synthesis of Bi2WOg nanoparticles and its electrochemical properties in different electrolytes for pseudocapacitor electrodes. Electrochimica Acta 109 720-731. 

Sankar, K. V., D. Kalpana, and R. K. Selvan. 2012. Electrochemical properties of microwave-assisted reflux-synthesized Mn304 nanoparticles in different electrolytes for supercapacitor applications. Journal of Applied Electrochemistry 42 463-470. 

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