Preyssler-type polyoxometalate-based crystalline materials for the electrochemical detection of H2O2

Abstract

Exploring an efficient non-enzymetic electrochemical sensor towards the detection of H₂O₂ is of great significance for the practical health monitoring and environmental analysis. In this study, four Preyssler-type polyoxometalate-based organic–inorganic hybrid materials were synthesized as non-enzymatic H₂O₂ electrochemical sensors having the formulae (H₂bimb)₆H₄[(Mn(H₂O)₃)₂(μ-bimb)(Mn(H₂O)₄(Mn(H₂O)₅)_0.75(Mn(H₂O)₄)_0.25(Na(H₂O)P₅W₃₀O₁₁₀))₂]·30.5H₂O (1), (H₂bimb)₃H₄[(Co(H₂O)₄)₂(μ-bimb)(Na(H₂O)P₅W₃₀O₁₁₀)]·10H₂O (2), {[(Cu(Hbimb)(H₂O)(μ-bimb)Cu(Hbimb)(H₂O))(Cu(H₂O)₂(μ-bimb)Cu(H₂O)₂)((Cu(H₂O)₂)_0.5(μ-bimb)(Cu(H₂O)₃)_0.5)H₂(Na(H₂O)P₅W₃₀O₁₁₀)]·12H₂O}_n (3) and (H₂bimb)₂H[((Zn(Hbimb)(H₂O)₂)_0.5)₂(Zn(Hbimb)(H₂O)₄)₂(Na(H₂O)P₅W₃₀O₁₁₀)]·8H₂O (4) (bimb = 1,4-bis(1H-imidazol-1-yl)benzene). In the compounds 1–4, Preyssler {P₅W₃₀} clusters show abundant coordination modes, and support the transition metal–organic fragments to give fascinating diverse networks. When used as electrochemical sensors for H₂O₂ detection, compounds 1–4 exhibited good electrocatalytic activities with high sensitivity and low detection limit. Among them, compound 2 showed the lowest limit of detection of 0.13 mM with a high sensitivity of 4.35 μA mM⁻¹ and fast response time of 1 s. Moreover, compound 2 displayed excellent electrochemical operational stability and anti-interference capacity. This study provides a good choice for the development of promising electrochemical non-enzymatic H₂O₂ sensors by employing Preyssler {P₅W₃₀}-based materials.