Nanomaterial with Core–Shell Structure Composed of {P(2)W(18)O(62)} and Cobalt Homobenzotrizoate for Supercapacitors and H(2)O(2)-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(4)[P(2)W(18)O(62)]@Co(3)(btc)(2) (abbreviated as {P(2)W(18)}@Co-BTC, H(3)btc = 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 {P(2)W(18)}. In the three-electrode system, it was found that {P(2)W(18)}@Co-BTC has the best supercapacitance performance, with a specific capacitance of 490.7 F g(−1) (1 A g(−1)) 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(−1)) and the energy density (11.36 Wh kg(−1)) are greater. In addition, as the electrode material for the H(2)O(2) sensor, {P(2)W(18)}@Co-BTC also exhibits a better H(2)O(2)-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 H(2)O(2) in human serum samples. This study provides a new strategy for the development of Dawson-type POMOF nanomaterial compounds.