Hierarchically Flower-like N‑Doped Porous Carbon Materials Derived from an Explosive 3‑Fold Interpenetrating Diamondoid Copper Metal–Organic Framework for a Supercapacitor

A peculiar
copper metal–organic framework (Cu-MOF) was synthesized by
a self-assembly method, which
presents a 3-fold interpenetrating diamondoid net based on the square-planar
CuII node. Although it exhibits a high degree of interpenetration,
the Cu-MOF still exhibits a one-dimensional channel, which provides
a template for constructing porous materials through the “precursor”
strategy. Furthermore, the explosive ClO4– ion, which resided in the channel, could induce the
quick decomposition of organic ingredients and release a huge amount
of gas, which is beneficial for the porosity of postsynthetic materials.
Significantly, we first utilize this explosive MOF to prepare a series
of Cu@C composites
through the calcination–thermolysis method at different temperatures,
which contain copper particles exhibiting various shapes and combinations
with the carbon substrate. Considering the hole-forming effect of
copper particles, Cu@C composites were etched by HCl to afford a sequence
of hierarchically flower-like N-doped porous carbon materials (NPCs),
which retain the original morphology of the Cu-MOF. Interestingly,
NPC-900, originating from the calcination of the Cu-MOF at 900 °C,
exhibits a more regular flower-like morphology, the largest specific
surface area, abundant porosities, and multiple nitrogen functionalities.
The remarkable specific capacitances are 138 F g–1 at 5 mV s–1 and 149 F g–1 at
0.5 A g–1 for the NPC-900 electrode in a 6 M potassium
hydroxide aqueous
solution. Moreover, the retention of capacitance remains 86.8% (125
F g–1) at 1 A g–1 over 2000 cycles,
which displays good chemical stability.
These findings suggest that NPC-900 can be applied as a suitable electrode
for a supercapacitor.