Electrocatalytic behavior toward nitrite of a hybrid film of fosfomolybdate and organomodified silica

ABSTRACT Nanostructured organic-inorganic hybrid materials are produced for the purpose of developing and / or enhancing a property of interest. One way of obtaining hybrid materials is by immobilizing an inorganic component in an organically modified silica (ormosil) network. In this study, a Keggin type polyoxometalate, phosphomolybdic acid (HPMo), was entrapped into a silica network modified with 3- (Trimethoxysilyl) propyl methacrylate (TMPM) and a thin film of this hybrid material was deposited on a gold electrode by the dip coating method. The electrochemical reactivity of this film was explored toward nitrite ion, where the catalytic electroreduction occurred at 0.0 V vs. Ag / AgCl. The linear concentration range obtained using cyclic voltammetry was 0.20 - 1.0 mmol L-1 in acidic medium pH 1.0. 31P Nuclear Magnetic Resonance spectroscopy showed that HPMo remains intact in the ormosil network. In addition, HPMo is interacting with methacrylate groups through hydrogen bonds as shown by infrared absorption spectroscopy. The hybrid film developed here could be used for the improvement of systems able of detecting nitrite.