Unravelling the role of crystal face on aldol condensation of furfural and acetone over CeO2

Catalytic aldol condensation of biomass-derived furfural (FAL) with acetone (AC) into the single-condensation product 4-(2-furyl)-3-buten-2-one (FAC) is a potential and promising strategy for biomass improvement process and still challenging. Metal oxides exposed different crystal facets can regulate their surface structure and adsorption activation ability, which can provide an opportunity to enhance aldol condensation performance. Here, nanoparticles-CeO 2 (P-CeO 2 ), nanorods-CeO 2 (R-CeO 2 ) and nanocubes-CeO 2 (C-CeO 2 ) with (111), (110) and (100) plane predominant exposure was prepared to explore their catalytic performance for the aldol condensation of FAL with AC to obtain FAC. The serial detailed characterizations, experimental results and density functional theory calculation revealed that R-CeO 2 with a dominant (110) facet possesses appropriate surface adsorption energy, abundant oxygen vacancy (Ov) and excellent acid-base properties, which can effectively boost the adsorption and activation of FAL and AC and reduce the barrier of aldol condensation reaction based on the acid-base catalysis mechanism. The work would reveal the influence of CeO 2 crystal facet on the aldol condensation and provide a broad potential for the rational design of metal oxide catalysts for other acid-base catalytic reactions.