The relationship between K⁺ and Mn vacancies and the significant effect of the K⁺ content on the structure, morphology and catalytic activity of birnessite-type MnO₂ for HCHO oxidation was systematically studied.

The exploration of active interfaces has attracted wide attention, especially in the field of catalysis. In this work, Ni/Fe layered double oxide supported Pt nanoparticles (Pt/LDO(N)) were prepared using a hydrothermal and colloid-impregnation method. The Pt/LDO(N) catalyst exhibited remarkable long-term catalytic stability and activity for HCHO oxidation compared with Pt/Fe₂O₃ and Pt/NiO. The Pt species were well dispersed on the LDO support, and strongly interacted with Fe and Ni by forming an active Pt–Fe/Ni interface. O₂ dissociation could happen at the active interface by creating coordinatively unsaturated iron sites, further providing adequate O⁻/O₂ ⁻ species to take part in HCHO oxidation. The in situ DRIFTS results indicated that the dioxymethylene and formate species were the main reaction intermediates, which could be further oxidized into CO₂ and H₂O through the involvement of active oxygen.

Open cells at the surface of α-MnO₂ provide adsorption and oxidative sites for CO oxidation.