Bimetallic ordered carbonaceous frameworks from Co- and Cu-porphyrin bimolecular crystals

Ordered carbonaceous frameworks (OCFs) are unique carbon alloys, having the advantages of both organic-based nanoporous frameworks and carbon materials: well-defined ordered structures, single-atom sites, high thermal/chemical stability, and electrical conductivity. Compared with reported carbon-metal catalysts with single-atom sites, OCFs contains a large amount of single-atomic metals (∼9 wt%), making OCFs a promising platform for various applications including electrocatalysis and energy storage/conversion. However, the types of metal species incorporated into OCFs have been limited to Ni and Fe. Herein, we demonstrate the synthesis of OCFs with single-atomic Co- and Cu-sites from the corresponding porphyrin crystals with eight ethynyl moieties. Since the Co- and Cu-porphyrin precursors have identical molecular structures except the metal species, they form identical supramolecular crystals. Thus, it is possible to form bimetallic supramolecular crystals simply by recrystallization of these two molecules together, and the resulting bimetallic crystals can be converted into bimetallic OCFs with developed microporosity. In the frameworks of the OCFs, single-atomic Co and Cu species are homogeneously dispersed and immobilized. The metal species embedded in the OCF framework are electrochemically active, and synergetic effect of Co and Cu in close proximity is observed.