Zeolite-encapsulated and clay-intercalated metal porphyrin, phthalocyanine and Schiff-base complexes as models for biomimetic oxidation catalysts: an overview

Advanced Zeolite, Materials Science

This article aims to review the electroanalytical applications of chemically modified electrodes involving silica and silica-containing matrices. After a brief introduction to silica chemistry, the implication of pure and grafted silicas in electrochemistry, as well as that of the silica-based materials originating from the sol-gel technology, will be discussed. The interest of silica-modified electrodes (SiO2-MEs) with respect to electroanalysis will be pointed out by means of several examples. In the last five years, successful applications of SiO2-MEs have been achieved. Among them, silica grafted with inorganic films or organic moieties was successfully applied to the selective preconcentration or the electrocatalytic detection of various analytes. Also, the ability of the sol-gel chemistry to encapsulate enzymes within a silica matrix without preventing its activity was exploited in the development of new amperometric biosensors. These promising fields are thought to lead to significant advances in the near future, because of the explosive growth in both the synthesis of novel mesoporous organically-modified silica-based materials and the huge development of sol-gel chemistry in tailoring and construction of new modified electrodes.

Analytical Applications of Silica-Modified Electrodes -A Comprehensive Review

Zeolite-modified electrodes in electroanalytical chemistry

meso-Tetrakis(p-carboxyphenyl)porphyrin (pTCPP), the atropoisomer (αααα) of meso-tetrakis(o-carboxyphenyl)porphyrin (oTCPP), and the ammonium salt of the meso-tetrakis(p-sulfonatophenyl)porphyrin (noted pTSPP) were intercalated into [Zn−Al] layered double hydroxide (LDH) using different preparative methods. Coprecipitation at constant pH in a porphyrinic solution of zinc and aluminum salts or anionic exchange of pTCPP on a [Zn−Al−Cl] precursor led to pure LDH phases, while products obtained from the calcination−reconstruction method on a [Zn−Al−Cl] precursor contain a significant amount of ZnO. Powder X-ray diffraction and UV−visible diffuse reflectance spectroscopy of LDH intercalated with pTCPP, oTCPP, and pTSPP show complete intercalation. Interlayer spacing ranging from 18.54 A for [Zn−Al−oTCPP] to 22.91 A for [Zn−Al−pTSPP] and 22.73 A for [Zn−Al−pTCPP], determined from PXRD patterns, reveal different orientations of the anionic macrocyles between the hyroxylated layers. This selective arrangement is ...

Bertrand De Vismes

Papers

Zeolite-porphyrin modified electrodes