Characterization of Mn species in mesoporous systems: An electrochemical study

Siliceous (MCM-41 type) and aluminophosphate (AlPO type) mesoporous materials have been synthesized trying to substitute the largest amount of Si and Al with Mn.The MnMCM-41 and MnAlPO obtained samples were characterized from the structural viewpoint and successively they underwent electrochemical testing by means of cyclic voltammetries in aqueous electrolytes in order to evaluate the electrochemical activity of the transition metal. In this communication, we report the results obtained from the structural and electrochemical characterization of these samples. The samples show the expected mesoporous structure with hexagonal array. In both systems, Mn is electrochemically active. In MnMCM-41 the two Mn(IV)/Mn(III) and Mn(III)/Mn(II) processes can be detected, while in MnAlPO Mn(III), originally present, shows only the Mn(IV)/Mn(III) reaction.