Sustainable conversion of biomass derived cellulose by using heterogeneous palladium based catalysts

This doctoral work is focused on the sustainable valorization of cellulose and its derivable molecules, through the application of the hydrogenolysis technology, by using heterogeneous Pd-based catalysts, in order to achieve products with high-added values, such as chemicals and fuels. In particular, the study of hydrogenolysis has been conceived with a bottom-up approach starting from polyols, namely sorbitol (C6) and shorter polyols (C5-C2), to approach finally the cellulose, with the aim to unravel the reactivity and selectivity, and to understand the mechanism of reactions involved. This study is mainly devoted toward the investigation of the bimetallic co-precipitated Pd/Fe3O4 catalyst, therefore its textural and structural characteristics have been deeply elucidated through several characterization techniques (XRD, TEM, H2-TPR, XPS and EXAFS), in order to highlight the key factors that determine its unique catalytic performances observed. A comparison of the performance of the bimetallic Pd/Fe3O4 catalyst and that of the commercial Pd/C was also performed. The importance of the mechanical pretreatment of cellulose (e.g. ball milling) and the role of water in its hydrogenolysis were also assessed. The last part of this doctoral study was dedicated to the investigation of hydrogen donor (H-donor) molecules, such as limonene and 2-propanol, studying the conversion of cellulose, by using the bimetallic Pd/Fe3O4 catalyst. These reactions were performed in presence and in absence of water, in order to understand its role.