Thermal Conversion of Core–Shell Metal–Organic Frameworks: A New Method for Selectively Functionalized Nanoporous Hybrid Carbon

TLDR

The study aims to bridge diverse carbon materials with metal‑organic frameworks to create nanoarchitectures with targeted functionalities. Core‑shell ZIF‑8@ZIF‑67 crystals were synthesized via a seed‑mediated growth approach. Thermal conversion of the ZIF‑8@ZIF‑67 crystals produced a nanoporous hybrid carbon with nitrogen‑doped cores and graphitic shells, the first such integration, and delivered a specific capacitance of 270 F g⁻¹ at 2 A g⁻¹.

Abstract

Core-shell structured ZIF-8@ZIF-67 crystals are well-designed and prepared through a seed-mediated growth method. After thermal treatment of ZIF-8@ZIF-67 crystals, we obtain selectively functionalized nanoporous hybrid carbon materials consisting of nitrogen-doped carbon (NC) as the cores and highly graphitic carbon (GC) as the shells. This is the first example of the integration of NC and GC in one particle at the nanometer level. Electrochemical data strongly demonstrate that this nanoporous hybrid carbon material integrates the advantageous properties of the individual NC and GC, exhibiting a distinguished specific capacitance (270 F·g(-1)) calculated from the galvanostatic charge-discharge curves at a current density of 2 A·g(-1). Our study not only bridges diverse carbon-based materials with infinite metal-organic frameworks but also opens a new avenue for artificially designed nanoarchitectures with target functionalities.