5. Nanostructured Bimetallic Pd-based Catalysts for the Valorization of Lignocellulosic Biomasses

This chapter is focused on the sustainable valorization of lignin and its derived molecules, through the application of the transfer hydrogenolysis technology, by using nanostructured bimetallic Pd-based catalysts, in order to achieve high added-value products. In particular, nanostructured bimetallic co-precipitated Pd-based catalysts (Pd-M systems), such as Pd/Fe₃O₄, Pd/Co and Pd/Ni, were used and their textural and structural properties have been deeply elucidated through several characterization techniques (XRD, TEM, SEM, H₂-TPR, XPS and EXAFS) in order to highlight the key factors that influence the peculiar catalytic activity in the reductive upgrading of lignin-derived aromatic ethers. Hydrogenolysis and transfer hydrogenolysis processes were focused on three model molecules of lignin: Benzyl Phenyl Ether (BPE), Phenethyl Phenyl Ether (PPE) and Diphenyl Ether (DPE) that mimic typical C-O lignin linkages, such as α-O-4, β-O-4 and 4-O-5 bonds. A comparison between the performance of bimetallic Pd-M catalysts and that of the commercial Pd/C is also included.