A highly active and stable Pd/15CoAlOx catalyst with Pd-Co composite interfaces for methane combustion

A series of Pd/yCoAlO (where y represents the Co/AlO mass ratio, ranging from 0 to 20.0 wt%) catalysts for CH combustion were synthesized, among which the Pd/15CoAlO catalyst exhibited excellent activity, stability and water resistance. HRTEM, XRD, and Raman results indicated that the Pd/15CoAlO catalyst comprised two phases, namely CoAlO and CoO. H-TPR, O-TPD, and in-situ DRIFTS revealed that Pd/15CoAlO featuring Pd-Co composite interfaces strengthened the anchoring of PdO and facilitated electron transfer between Pd-Co interfaces. Moreover, active oxygen species were enriched at the interface, which promoted the reaction pathway involving the change from methoxy to formate, rather than from methyl to formate. Multiple characterizations and analyses indicated that Pd/15CoAlO exhibited a MSI weaker than the Pd-CoO interface but stronger than that observed at the Pd-AlO interface. The appropriate level of interaction avoided the excessive oxidation of Pd, ensuring the presence of a substantial quantity of unsaturated Pd sites.