Incorporating Cobalt to Promote the In Situ Reduction of Cu–Co/CeO₂ Catalysts for Enhancing the Hydrogenation of Furfural to Furfuryl Alcohol

Developing Cr-free and non-noble metal catalysts for the selective hydrogenation of biomass-derived furfural (FAL) to furfuryl alcohol (FOL) is highly desirable. Herein, monometallic Cu/CeO2, Co/CeO2, and bimetallic CuCo/CeO2 catalysts with different amounts of cobalt were prepared by a simple coprecipitation method. The prepared catalysts were directly applied in FAL hydrogenation to FOL under near-industrial conditions without prereduction. It was observed that only 7.8 and 2.0% conversion of FAL was achieved over 10Cu/CeO2 and 10Co/CeO2 catalysts, respectively, while the conversion of FAL dramatically increased to 97.2% with 97.8% FOL selectivity by using 10Cu10Co/CeO2 under identical reaction conditions. The physicochemical properties of the catalysts were investigated by XRD, TEM, BET, H2-TPR, and XPS. The characterization results revealed that the CuO species over the Cu-based catalysts could be reduced in situ to metallic Cu during the reaction. Moreover, the introduction of Co to the 10Cu/CeO2 catalyst resulted in 10Cu10Co/CeO2 exhibiting a smaller Cu particle size, favoring the formation of Cu0 active species and thus enhancing the catalytic performance. A possible reaction pathway and mechanism for FAL hydrogenation over the bimetallic CuCo/CeO2 catalysts was proposed.