Microheterogeneous photocatalysis

Cozzoli, P.D., E. Fanizza, R. Comparelli, M.L. Curri, A. Agostiano and D. Laub (2004b). Role of metal nanoparticles in Ti02/Ag nanocomposite-based microheterogeneous photocatalysis. Journal of Physical Chemistry B, 108(28), 9623-9630. 

Part V, which is about interfacial photocatalysis, includes such topics as nanochemistry, nanoparticles, self-organized microheterogeneous structures, photosensitizers. 

Catalysis and Photocatalysis at Polarized Molecular Interfaces An Electrochemical Approach to Catalytic Processes Based on Two-Phase Systems, Self-Organized Microheterogeneous Structures, and Unsupported Nanoparticles... 

The main objective of this chapter is to illustrate how fundamental aspects behind catalytic two-phase processes can be studied at polarizable interfaces between two immiscible electrolyte solutions (ITIES). The impact of electrochemistry at the ITIES is twofold first, electrochemical control over the Galvani potential difference allows fine-tuning of the organization and reactivity of catalysts and substrates at the liquid liquid junction. Second, electrochemical, spectroscopic, and photoelectrochemical techniques provide fundamental insights into the mechanistic aspects of catalytic and photocatalytic processes in liquid liquid systems. We shall describe some fundamental concepts in connection with charge transfer at polarizable ITIES and their relevance to two-phase catalysis. In subsequent sections, we shall review catalytic processes involving phase transfer catalysts, redox mediators, redox-active dyes, and nanoparticles from the optic provided by electrochemical and spectroscopic techniques. This chapter also features a brief overview of the properties of nanoparticles and microheterogeneous systems and their impact in the fields of catalysis and photocatalysis. 

In Section II.C, we described the reactivity of adsorbed dye species at liquid liquid junctions in heterogeneous photoredox reactions. The properties of these systems can be used to catalyze electron-transfer processes. The behavior of dyes at interfaces has been vigorously studied in micelles and microemulsion systems, and many excellent reviews and books are available on this subject [94-97]. In this section, we shall consider some basic aspects of photoprocesses in microheterogeneous systems that are relevant to polarizable ITIES. This is not intended to cover comprehensively the recent developments in the active area of photochemistry at organized assemblies, but to highlight how spatial confinement, hydrophilic hydrophobic forces, and local potentials can affect the course of a photochemical process. We shall also revise some recent developments in photocatalysis and photosynthesis at polarizable liquid liquid interfaces, highlighting advantages and limitations in relation to two-phase catalysis. 

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