Promoter Effect of Pt on Zr Catalysts to Increase the Conversion of Furfural to γ-Valerolactone Using Batch and Continuous Flow Reactors: Influence of the Way of the Incorporation of the Pt Sites

The valorization of biomass and its transformation into fuels are highly interesting due to the abundance of biomass and its almost neutral carbon emissions. In this article, we show the production of γ-valerolactone (GVL), a valuable product, from furfural (FF), a compound that can be easily obtained from biomass. This FF to GVL transformation involves a catalytic cascade reaction with two hydrogenation steps. Pt and/or Zr supported on sepiolite catalysts have been prepared and tested in the FF transformation reaction. A physical mixture of a Zr-based and a Pt-based catalyst has reached a yield to GVL of ca. 50% after 16 h at 180 °C. This performance largely exceeds that obtained by each of the single Pt or single Zr metal catalysts independently, showing a strong synergistic effect. These data suggest that each metal (Pt and Zr) plays an important and complementary role in different reaction steps. Furthermore, the physical mixture appears to be much more efficient than bimetallic Pt/Zr catalysts synthesized with the same amount of metals. The role of the type of acidity and the oxidation state of the surface platinum species on the catalytic performance has been discussed. Moreover, this reaction has been carried out in batch and continuous flow reactors, and a comparative study between the two operation modes has been undertaken. A certain correlation between the catalytic results obtained by both operation modes has been found.