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

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.