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(H 2 O) 3 (μ-bimb)) 0.5 (Mn(H 2 O) 4 )(Mn(H 2 O) 5 ) 0.5 (AgP 5 W 30 O 110 )) 2 ]·29H 2 O ( 1 ), [(Cu(Hbimb)(H 2 O) 2 (μ-bimb)Cu(Hbimb)(H 2 O))(Cu(H 2 O) 2 (μ-bimb)Cu(H 2 O) 3 )((Cu(H 2 O) 2 ) 0.5 (μ-bimb)(Cu(H 2 O) 3 ) 0.5 )H 2 (AgP 5 W 30 O 110 )]·12.5H 2 O ( 2 ), (H 2 bimb) 2 H[(Zn(Hbimb)(H 2 O) 4 (Zn(Hbimb)(H 2 O) 2 ) 0.5 ) 2 (AgP 5 W 30 O 110 )]·12H 2 O ( 3 ), and (H 2 bimb) 3 H 2 [(Ag(H 2 O) 2 ) 0.5 (Ag(Hbimb)Ag(Hbimb)(μ-bimb)Ag)(Ag(H 2 O) 2 ) 0.5 (AgP 5 W 30 O 110 )]·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 [AgP 5 W 30 O 110 ]·18H 2 O (abbreviated as K-{AgP 5 W 30 }) as a precursor. In 1 - 4 , {AgP 5 W 30 } clusters integrating the merits of Ag + and {P 5 W 30 } 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 (H 2 O 2 ); 4 possesses the highest sensitivity of 195.47 μA·mM -1 ·cm -2 for H 2 O 2 detection. Most importantly, the average level of H 2 O 2 detection of these {AgP 5 W 30 }-based materials outperforms that of Na-centered Preyssler-type {NaP 5 W 30 } and most Keggin-type POM-based materials. The performances of such {AgP 5 W 30 } materials mainly stem from the unique advantage of high-negatively charged {AgP 5 W 30 } clusters together with the good synergistic effect between {AgP 5 W 30 } and TMs. This work expands on the research of high-efficiency POM-based nonenzymatic electrochemical H 2 O 2 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.