Nanomaterial with Core-Shell Structure Composed of {PWO} and Cobalt Homobenzotrizoate for Supercapacitors and HO-Sensing Applications.

Designing and preparing dual-functional Dawson-type polyoxometalate-based metal-organic framework (POMOF) energy storage materials is challenging. Here, the Dawson-type POMOF nanomaterial with the molecular formula CoK[PWO]@Co(btc) (abbreviated as {PW}@Co-BTC, Hbtc = 1,3,5-benzylcarboxylic acid) was prepared using a solid-phase grinding method. XRD, SEM, TEM et al. analyses prove that this nanomaterial has a core-shell structure of Co-BTC wrapping around the {PW}. In the three-electrode system, it was found that {PW}@Co-BTC has the best supercapacitance performance, with a specific capacitance of 490.7 F g (1 A g) and good stability, compared to nanomaterials synthesized with different feedstock ratios and two precursors. In the symmetrical double-electrode system, both the power density (800.00 W kg) and the energy density (11.36 Wh kg) are greater. In addition, as the electrode material for the HO sensor, {PW}@Co-BTC also exhibits a better HO-sensing performance, such as a wide linear range (1.9 μM-1.67 mM), low detection limit (0.633 μM), high selectivity, stability (92.4%) and high recovery for the detection of HO in human serum samples. This study provides a new strategy for the development of Dawson-type POMOF nanomaterial compounds.