Unraveling the deactivation mechanism and stability enhancement of cobalt-based heterogeneous Co3O4/g-C3N4 catalysts in CO2 hydrogenation

Abstract

Cobalt is an interesting candidate to catalytically convert CO₂ gas to value-added chemicals through a thermal hydrogenation reaction. However, its catalytic activity and long-term stability are strongly hindered by its dispersion and phase state. In this work, we deeply investigate the dispersion and reduction behavior of a Co₃O₄ nano-sized catalyst and precisely optimize its catalytic properties in CO₂ hydrogenation by modulating the dispersion and metal–support interactions. Finally, it achieves a stable CO₂ conversion of 28% with CH₄ selectivity above 85% during a 30 hour longevity test. The improvement is attributed to the strengthened metal–support interaction between Co₃O₄ nanoparticles (NPs) and the g-C₃N₄ carrier, which stabilizes the active metallic Co species and significantly boosts catalytic activity and durability. This study provides valuable insights into the structural requisites for optimizing CO₂ hydrogenation catalysts and offers a feasible strategy for designing efficient non-noble metal catalysts for CO₂ utilization.