Nanomaterial with Core-Shell Structure Composed of {P₂W₁₈O₆₂} and Cobalt Homobenzotrizoate for Supercapacitors and H₂O₂-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 CoK4[P2W18O62]@Co-3(btc)(2) (abbreviated as {P2W18}@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 {P2W18}. In the three-electrode system, it was found that {P2W18}@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 H2O2 sensor, {P2W18}@Co-BTC also exhibits a better H2O2-sensing performance, such as a wide linear range (1.9 mu M-1.67 mM), low detection limit (0.633 mu M), high selectivity, stability (92.4%) and high recovery for the detection of H2O2 in human serum samples. This study provides a new strategy for the development of Dawson-type POMOF nanomaterial compounds.