A host–guest compound formed by Cu3[P2W18O62] and HKUST-1 with capacitance and H2O2 sensing properties

Polyoxometalate-based metal-organic frameworks (POMOFs) have received wide attention in supercapacitors and H2O2 detection due to their possession of the rich redox active sites of polyoxometalates (POMs) and the ordered structure of metal-organic frameworks (MOFs). In this study, we successfully synthesized a host-guest Cu3[P2W18O62]@HKUST-1 (HRBNU-7) compound by a grinding method. Cu3[P2W18O62] successfully entered the HKUST-1 pores as confirmed by the results of infrared (IR) spectroscopy, powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The specific capacitance of HRBNU-7 is 318.6 F g-1 at 1 A g-1 in a three-electrode system using nickel foam as the collector. The specific capacity retention is 92.36% after 5000 cycles. The assembled symmetrical supercapacitor (SSC) achieved a high energy density of 10.58 W h kg-1 at a power density of 500.00 W kg-1. In addition, HRBNU-7 exhibits excellent electrochemical detection of H2O2, including a wide linear range of 0.5 μM-0.3 mM, a low detection limit of 0.17 μM, and excellent selectivity and stability, and it can be effectively utilized for the analysis of H2O2 content in actual serum samples. These excellent properties are attributed to the unique redox activity of Cu3[P2W18O62] and the high specific surface area of HKUST-1. This work offers a strategy for exploring POMOFs as electrode materials in supercapacitors and electrochemical sensors.