A 3D POMOF based on a {AsW12} cluster and a Ag-MOF with interpenetrating channels for large-capacity aqueous asymmetric supercapacitors and highly selective biosensors for the detection of hydrogen peroxide

Abstract

{AsW₁₂O₄₀} clusters were grafted onto Ag-MOF to yield two 3D polyoxometallate-based metal organic frameworks (POMOFs), (imi)₂[{Ag₃(tpb)₂}₂(H₂O){AsW₁₂O₄₀}₂]·6H₂O (1) and [(Ag₇bpy₇Cl₂){AsW^V₂W^VI₁₀O₄₀}]·H₂O (2) (imi = imidazole; tpb = 1,2,4,5-tetrakis(4-pyridyl)benzene; bpy = 4,4′-bipyridyl). These compounds are complicated 3D networks with intersecting channels and novel topologies. They exhibit larger capacitances (929.7 and 986.1 F g⁻¹ at a current density of 3 A g⁻¹), superior rate capabilities, higher capacity retention rates, boosting conductivities and electrocatalytic activities compared to those of their maternal POM, and this can be ascribed to the introduction of Ag-MOF, interpenetrating channels, and the unique stability of the POMOF. An aqueous asymmetric supercapacitor equipment, assembled with 2-CPE, displays remarkable energy density (16.1 W h kg⁻¹) with a power density of 1748.9 W kg⁻¹ and durable cyclic stability. The practical application capability as a power supply device can be confirmed by lighting a red light-emitting diode. Moreover, 2-GCE as a H₂O₂ biosensor reveals a lower detecting limit (0.48 μM), a wider linear range (1.43 μM to 1.89 mM), high selectivity and high reproducibility, and this was further demonstrated by detecting H₂O₂ in real blood serum samples.