UC Santa Barbara

Lignocellulosic biomass is composed of lignin, cellulose, and hemicellulose. Lignin is naturally formed renewable aromatic biopolymer; the cellulose and hemicellulose are polysaccharides. By far, the “second generation” biorefineries mainly use the value of cellulose pulp in paper industries or in making low-value chemicals such as ethanol while more than 98% of lignin is discarded into direct combustion. The valorizations of lignin and polysaccharides are still under development. Herein, we have studied the heterogeneous catalytic conversion of lignin monomers and polysaccharides with Ru/C catalyst with different metal oxides for making a variety of value-added chemicals. For instance, we developed a Ru/C and Nb2O5 co-catalyst system to funnel different lignin monomers into C9 hydrocarbons which could potentially be used as drop-in fuels. We also investigated the Ru/C and WOx co-catalysts to convert the polysaccharides into diols and polyols. By performing the isotopic reactions and time programmed sampling, our study disclosed the mechanisms and kinetics of the catalytic reactions. To achieve the goal of biomass valorization, we also developed a purification method to avoid catalyst poisoning by the contaminations from raw biomass and thus facilitated the sustainable utilization of native lignin into valuable chemicals.