Electrocatalysis at Microparticulate Deposits of Porous Materials

Microparticulate deposits of inorganic solids mechanically transferred to the surface of inert electrodes or dispersed in carbon paste or composite electrodes 

FIGURE 3.1 CVs for silicomolybdate-modified graphite electrodes immersed into 0.2 M H2SO4 containing (a) 0.2 and (b) 0.0 mM concentrations of Cr(VI). Potential scan rate, 100 mV/sec. 

This scheme can be extended to nonconducting or semiconducting nanoporous solids incorporating redox-active centers via chemical doping prompted by sol-gel methodologies (Domenech and Alarcon, 2002b, 2003 Domenech et al. 2004b-d). Eventually, the materials can be electrochemically modified (Rolison and Bessel, 2000). 

As occurring for thin films of redox polymers, there are three elements of porous electrode behavior crucial to its performance in electrocatalysis the transport of a solution reactant to the catalytic sites within the porous system, the transport of electrolyte charge-balancing ions, and the electron transport across the solid, a process responsible for the regeneration of the initial oxidation state of the catalyst. 

FIGU RE 3.2 Schematic diagram of electrocatalysis performed with an immobilized catalyst. 

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