Importance of Edge and Corner Sites on CeO₂ Nanoparticles for Direct Conversion of Methane to Methanol

Abstract

The effect of CeO2 nanoparticle size on catalysis performance during continuous direct conversion of CH4 to CH3OH at low temperatures was studied by experiment and density functional theory (DFT). Methanol is the only liquid-phase product, and small CeO2 nanoparticles are beneficial for methanol yield. Water could undergo dissociative adsorption on different CeO2 sizes at 180 °C. As a result, OH blocked Ce sites, and methanol was synthesized through the reaction CH4* + OH* → CH3OH* + H*. During the reaction, the main role of H2O is to provide oxygen species for the conversion of methane to methanol, and O2 is used to prevent CeO2 excessive reduction. In summary, the CH3OH yield is related to low-coordinate edge or corner Ce atoms of CeO2.