Inorganic‐organic Microporous Solid of Wells‐Dawson Type Polyoxometalate: Synthesis, Characterization, and Electrochemical Properties

An inorganic‐organic hybrid solid (H 6/5 bppy) 5 [P 2 W 18 O 62 ]·4.5H 2 O ( 1 ) (bppy = 4‐(5‐(4‐bromophenyl)pyridin‐2‐yl)pyridine) was hydrothermally synthesized by using pre‐constructed Wells‐Dawson type salt α‐K 6 P 2 W 18 O 62 ·15H 2 O as inorganic moiety. The crystal structure keeps integrated and steady under the interactions together of aryl packing, hydrogen bonding and halogen bonding. X‐ray single crystal structure analysis reveals that compound 1 contains cavities with the sizes of about 6 × 8Å, in which H 2 O molecules are captured. The hybrid was used as a solid bulk modifier to fabricate a three‐dimensional bulk‐modified carbon paste electrode ( 1 ‐CPE) by direct mixing. The electrochemical and electrocatalytic behavior of the 1 ‐CPE has been studied in detail. The results exhibit that the redox ability of the Wells‐Dawson polyanions can be maintained in the hybrid solid, which has a good electrocatalytic activity toward the reduction of bromate and hydrogen peroxide. A hydrodynamic voltammetric experiment was performed to characterize the electrode as an amperometric sensor for the determination of hydrogen peroxide. The 1 ‐CPE showed long‐term stability and excellent reproducibility of surface renewal.