Fabrication of Pd/CeO2 nanocubes as highly efficient catalysts for degradation of formaldehyde at room temperature

Abstract

Eliminating indoor formaldehyde (HCHO) pollution at room temperature is highly needed to improve the environment while saving energy. Herein, Pd/CeO₂ catalysts with different morphologies of the CeO₂ support were employed to investigate their performance for HCHO oxidation. The Pd/CeO₂ nanocube (Pd/CeO₂-C) catalyst exhibited excellent catalytic activity compared to commercial CeO₂ and CeO₂ nanorods. HCHO can be completely converted into CO₂ and H₂O over the Pd/CeO₂-C (0.64 wt% Pd) catalyst at a weight hourly space velocity of 36 000 mL g⁻¹ h⁻¹ at room temperature. Multiple characterization results confirmed that the strong interfacial interaction between Pd and the CeO₂-C support guarantees a high percentage of metallic Pd on the CeO₂-C surface and its high dispersion, which is crucial for the oxidation of formaldehyde at low temperature. The in situ diffuse reflectance infrared Fourier transform results indicated that CO, formate and dioxymethylene species are the main intermediates over the Pd/CeO₂-C catalyst, and the active O species is responsible for their decomposition and oxidation. This work may promote the practical application of high performance Pd-based catalysts for indoor HCHO purification and related catalytic processes.