Redox behaviours and electrocatalytic properties of copper within Dawson structure-derived sandwich heteropolytanions [Cu_4(H_2O)_2(X_2W_(15)O_(56)_2]~(16-) (X = P or As)

摘要

Two Cu~(2+) sandwich-type heteropolyanions with the Dawson moiety [X_2W_(15)O_(56)]~(12-) (X = P or As) were synthesized. Their oxidized forms are stable from pH 3 to at least pH 7. Their characterization by cyclic voltammetry revealed the stepwise reduction of Cu~(2+) centers within these heteropolyanions before deposition of Cu~0 on the glassy carbon electrode surface. The presence of chloride ions in the supporting electrolyte does not induce the extraction of the copper centers from the heteropolyanions. These sandwich-type complexes are shown to have electrocatalytic properties towards the reductions of nitrate, nitrite, dioxygen and hydrogen peroxide. Electrochemical characterization of these complexes is offered for the first time.