Synthesis of five polyoxometalate-based compounds by using hydrothermal one pot method: Structures, supercapacitor, electrocatalytic and photocatalytic properties

Abstract

Five polyoxometalate (POM) based compounds were synthesized by traditional hydrothermal method, namely {Co2(HTPT)2(H2O)2[Mo8O27]} (1), {Co2(TPT)2(H2O)6}(β-Mo8O26)·4H2O (2), {Co2(TPT)2(H2O)2(δ-Mo8O26)}·2H2O (3), {M(TPT)2(H2O)2}(Mo6O19) (M = Co 4, Ni 5) (TPT = 3-(4-terahydro-2H-pyran-4-yl)methyl)-4H-1,2,4-triazol-3-yl)pyridine). Compounds 1−3 were obtained in one pot, realizing efficient utilization of the hydrothermal method. The photocatalytic activities of compounds 1, 2, 4 and 5 were evaluated by the degradation of Methylene blue (MB) and Rhodamine B (RhB) and the reduction of Cr6+. The effects of the amount of catalyst and the pH of the system on the photocatalytic performance were also studied. Experimental studies have shown that compounds 1 and 4 also exhibit good bifunctional electrocatalytic activity for reducing NO2−, Cr6+ and H2O2, but also oxidizing AA (Ascorbic Acid). Compounds 1, 2, 4 and 5 can serve as amperometric sensors for NO2− and Cr6+. Compounds 1 and 4 own properties of capacitor materia.