Mesoporous Co3O4 derived from Co-MOFs with different morphologies and ligands for toluene catalytic oxidation

Toluene is one of the most toxic pollutants of the air and catalytic oxidation is an effective technology for toluene removal. A series of mesoporous Co3O4 catalysts for toluene oxidation were successfully synthesized via pyrolysis of different morphologic Co-MOFs, involving ZIF-67, MOF-74 and ZSA-1 with N-donor, O-donor and N-O-donor linkers, respectively. The resulting Co3O4 catalysts exhibited different physicochemical properties such as exposed facets, Co3+/Co2+, Oads/Olatt, specific surface area, low temperature reducibility and so on. The morphology of the parent Co-MOFs and the content of C, N and O in the linkers are both pivotal in these differences. The Co3O4 catalysts also displayed differential catalytic activity and stability for toluene oxidation in the catalytic test. T90% of toluene over the Co3O4 catalysts is in the following order: ZSA-1-Co3O4 (N-O-ligand with octahedra shape) > MOF-74-Co3O4 (O-ligand with rod shape) > ZIF-67-Co3O4 (N-ligand with dodecahedral shape).