Efficient Electrochemical Detection of Hydrogen Peroxide Based on Silver-Centered Preyssler-Type Polyoxometalate Hybrids

Four polyoxometalate (POM)-based organic-inorganic hybrid compounds, namely, (H(2)bimb)(6)H-8[((Mn(H2O)(3)(mu-bimb))(0.5)(Mn(H2O)(4))(Mn(H2O)(5))(0.5)(AgP5W30O110))(2)]center dot 29H(2)O (1), [(Cu(Hbimb)(H2O)2(mu-bimb)Cu(Hbimb)(H2O))(Cu(H2O)(2)( mu-bimb)Cu(H2O)(3))((Cu(H2O)(2))(0.5)(mu-bimb)(Cu(H2O)(3))(0.5))H-2(AgP5W30O110)]center dot 12.5H(2)O (2), (H(2)bimb)(2)H[(Zn-(Hbimb)(H2O)(4)(Zn(Hbimb)(H2O)(2))(0.5))(2)(AgP5W30O110)]center dot 12H(2)O (3), and (H(2)bimb)(3)H-2[(Ag(H2O)(2))(0.5)(Ag(Hbimb)Ag(Hbimb)(mu-bimb)Ag)(Ag( H2O)(2))(0.5)(AgP5W30O110)]center dot 7H(2)O (4) (bimb = 1,4-bis(1H-imidazol- 1-yl) benzene), were hydrothermally synthesized using a silver-centered Preyssler-type POM K-14[AgP5W30O110]center dot 18H(2)O (abbreviated as K-{AgP5W30}) as a precursor. In 1-4, {AgP5W30} clusters integrating the merits of Ag+ and {P5W30} units are modified by different transition metal (TM)-organic fragments to extend the structures into three-dimensional frameworks. As nonenzymatic electrochemical sensor materials, 1-4 show good electrocatalytic activity, high sensitivity, and a low detection limit for detecting hydrogen peroxide (H2O2); 4 possesses the highest sensitivity of 195.47 mu A.mM(-1).cm(-2) for H2O2 detection. Most importantly, the average level of H2O2 detection of these {AgP5W30}-based materials outperforms that of Na-centered Preyssler-type {NaP5W30} and most Keggin-type POM-based materials. The performances of such {AgP5W30} materials mainly stem from the unique advantage of high-negatively charged {AgP5W30} clusters together with the good synergistic effect between {AgP5W30} and TMs. This work expands on the research of high-efficiency POM-based nonenzymatic electrochemical H2O2 sensors using Ag-containing POMs with high negative charges, which is also of great theoretical and practical significance to carry out health monitoring and environmental analysis.

Automated summary

Four POM-based organic-inorganic hybrid compounds were synthesized and their structures were expanded into three-dimensional frameworks by modifying {AgP5W30} clusters. These materials showed good electrocatalytic activity and high sensitivity as nonenzymatic electrochemical sensor materials for detecting hydrogen peroxide (H2O2), with low detection limit. Compared to other types of POM-based materials, these {AgP5W30}-based materials exhibited superior performance, which can be attributed to the high-negative charge of {AgP5W30} clusters and the synergistic effect with transition metals.