Synthesis and study by FTIR, 31P NMR and electrochemical impedance spectroscopy of vanadium zinc phosphate glasses prepared by sol–gel route

Abstract

Ternary phosphate glasses of the system (ZnO)(0.45−x)–(P2O5)(0.55−y)–(V2O5)z, (y=0; x=z=0.01, 0.1; 0.2) and (x=0, y=z=0.1; 0.2) are prepared via the sol–gel process using zinc acetate, ammonium metavanadate and phosphoric acid as precursors. Spectroscopic investigations reveal a phosphate glass system depolymerization by systematic conversion of PO3− metaphosphate chains into (P2O7)4− pyrophosphate, with the formation of P–O–V and V–O–V bonds, which replace P–O–P ones. Heat treatment of the dried xerogels containing 10% of V2O5 at temperatures 400–600°C shows a similar trend in their infrared spectrum then that of glass obtained by melt quenching at 1000°C. Inhibitive effect of the glass composition (ZnO)0.45–(P2O5)0.45–(V2O5)0.1 obtained at 600°C and 1000°C in simulated water was studied by electrochemical impedance spectroscopy (EIS). Inhibitory efficiency for both samples is the same ~95%.