OXOMETALATE-CLAY-MODIFIED ELECTRODES - SYNTHESIS AND PROPERTIES OF ANIONIC CLAYS PILLARED BY METATUNGSTATE

Three anion-pillared hydrotalcite clays or layered double hydroxides, have been prepared corresponding to the general formula Zn2Al(X).mH2O, where X=Cl-, NO3-, or terephthalate dianion (TA). To the best of our knowledge, Zn2Al(TA).mH2O has been prepared for the first time. These clays are used to modify electrode surfaces and the exchanges of the different anions under mildly acidic conditions with metatungstate anions have been monitored by cyclic voltammetry and compared. They proceed smoothly to give the isopolymetalate-pillared hydrotalcite, the best results being obtained with Zn2Al(TA). The best conditions for preparation of these electrodes and the stability of the final assembly in various conditions have been studied.