Synthesis of nanoporous carbon-cobalt-oxide hybrid electrocatalysts by thermal conversion of metal-organic frameworks.

ABSTRACT

Nanoporous carbon-cobalt-oxide hybrid materials are prepared by a simple, two-step, thermal conversion of a cobalt-based metal-organic framework (zeolitic imidazolate framework-9, ZIF-9). ZIF-9 is carbonized in an inert atmosphere to form nanoporous carbon-metallic-cobalt materials, followed by the subsequent thermal oxidation in air, yielding nanoporous carbon-cobalt-oxide hybrids. The resulting hybrid materials are evaluated as electrocatalysts for the oxygen-reduction reaction (ORR) and the oxygen-evolution reaction (OER) in a KOH electrolyte solution. The hybrid materials exhibit similar catalytic activity in the ORR to the benchmark, commercial, Pt/carbon black catalyst, and show better catalytic activity for the OER than the Pt-based catalyst.