Improved supercapacitors and water splitting performances of Anderson
{MnMo6} by assembling with Zn-MOF as the host-guest structure
Abstract
Improving performance by combining polyoxometalates (POM) clusters with
metal-organic frameworks (MOFs) containing different transition metals
presents a challenge. Here, a solvothermal method was first used to
synthesized a POM-based metal-organic frameworks (POMOFs)
Zn[N(C4H9)4][MnMo6O18{(OCH2)3CNH2}2]@Zn3(C9H3O6)2·6C3H7NO
(HRBNU-5, which Zn[N(C4H9)4][MnMo6O18{(OCH2)3CNH2}2]·3C3H7NO
({Zn[MnMo6]}), Zn3(C9H3O6)2·3C3H7NO (Zn-BTC)) . Structural
characterization revealed that the compound is host-guest structure with
Zn-BTC encapsulation {Zn[MnMo6]}. In the three-electrode system,
its specific capacitance is 851.3 F g-1 at a current density of 1 A g-1,
and it remains highly stable (97.2%) after 5000 cycles. In the
symmetrical supercapacitor (SSC) system, HRBNU-5 still performs well
with energy density and power density of 11.02 Wh kg-1 and 605.7 W kg-1
at 1 A g-1, respectively. Besides, it shows good catalytic performance
in 1 M KOH, with overpotentials and Tafel slopes for hydrogen and oxygen
evolution reactions of 177 mV (η10 HER), 126.9 mV dec-1 and 370 mV (η50
OER), 36.3 mV dec-1, respectively, outperforming its precursors and most
reported literature. The good activity is ascribed to host-guest
structure, high conductivity of HRBNU-5 for electron-transfer, and
porous structure that facilitates mass transport. This provides new
inspiration for the design of Anderson-type POMOFs electrode materials
with multiple active sites and a clear structure.