Complexity of a Co₃O₄ System under Ambient-Pressure CO₂ Methanation: Influence of Bulk and Surface Properties on the Catalytic Performance

Although using supported noble-metal catalysts for CO2 hydrogenation is an effective solution due to their excellent catalytic properties, metal oxide supports themselves can exhibit good activity being more economically feasible. This work focuses on investigating the complexity of Co3O4 system during methanation reaction, which usually accompanied by formation unstable dispersions cobalt and metallic Co. Herein, we have tested different types Co3O4: synthetically prepared mesoporous m-Co3O4 (BET surface area, 95 m2/g) commercial c-Co3O4 15 m2/g; purchased from Merck) in reaction under reduction temperatures (273–673 K). The temperature was adjusted 573 K both reach optimal Co/cobalt ratio consequently best performance. active (CO2 conversion 95%) stable at higher compared 63%) its morphology-induced ∼66 times basicity. DRIFTS results showed differences detected species: formate observed proven contribute total methane formation. It revealed that bulk properties such as morphology, oxidation states, acid–base presence defect sites directly affect performance mechanism. Furthermore, 1% 5 nm Pt nanoparticles were loaded onto Co3O4s check competitiveness catalysts. study evidences a cheap noble-metal-free catalyst consisting with competitive ∼100% CH4 selectivity.