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 d ifferent anions under mildly acidic conditions with metatungstate anio ns have been monitored by cyclic voltammetry and compared. They procee d smoothly to give the isopolymetalate-pillared hydrotalcite, the best results being obtained with Zn2Al(TA). The best conditions for prepar ation of these electrodes and the stability of the final assembly in v arious conditions have been studied.