Mesoporous Co₃O₄ Nanoparticles with Enriched Oxygen Defects for Efficient NO Oxidation

Abstract

Catalytic conversion of NO to NO 2 stands as a pivotal step governing NO x purification technology, with its effectiveness relying heavily on the utilization of high-performance catalysts. Herein, we harness a facile ligand-assisted self-assembly strategy to fabricate mesoporous Co 3 O 4 with abundant oxygen vacancies (M-Co 3 O 4 ), aiming at improving the activity of NO oxidation. For comparison, Co 3 O 4 nanoflakes (F-Co 3 O 4 ) and bulk Co 3 O 4 (B-Co 3 O 4 ) were synthesized from a hydrothermal method and direct calcination of cobalt nitrate, respectively. Activity results reveal that M-Co 3 O 4 can oxidize 88% of NO at 275 °C under a GHSV of 180,000 h −1 , surpassing both F-Co 3 O 4 (70% at 325 °C) and B-Co 3 O 4 (66% at 325 °C).Extensive characterizations indicate that the exceptional activities of M-Co 3 O 4 are predominantly attributed to the synergistic effects of its surface Co 2+ species, weak Co−O bond strength, and high mobility of surface lattice oxygen. This work lays the groundwork for the advancement of high-performance Co 3 O 4 -based catalysts for atmospheric contaminants remediation.