(668c) Electrocatalytic Hydrogenation of Lignin-Derived Bio-Oil Model Compounds Using Ruthenium on Activated Carbon Cloth to Produce Liquid Fuel Intermediates and Value-Added Products

Biomass fast pyrolysis (BFP) uses heat in the absence of oxygen to convert biomass to bio-oil, biochar and combustible gas. The biochar co-product can be used for the removal of pollutants in the environment and has potential for use in soil amendment and carbon sequestration. The combustible gas co-product is typically burned for process heat needed by the pyrolysis system. The major product, bio-oil, has the potential to displace liquid hydrocarbon fuels; however, bio-oil is highly oxygenated, corrosive, low in energy content and unstable during storage. Electrocatalytic hydrogenation (ECH) is employed to reduce and deoxygenate reactive compounds and improve bio-oil properties. The present study particularly focuses on the electrocatalytic stabilization of compounds derived from the pyrolytic depolymerization of lignin. As lignin is a component of biomass comprising up to 30% of the mass and 40% of the energy stored in biomass, it offers great potential as feedstock for BFP. Lignin model compounds representative of bio-oil components were subjected to ECH under mild conditions using ruthenium on activated carbon. To date, several model lignin monomers and dimers have been reduced to simpler compounds such as cyclohexanol and phenol. The effect of different electrolytes, substrate concentrations, current density, and catalyst preparation methods on conversion and current efficiency was studied. The coupling of pyrolysis and electrocatalysis for depolymerization and upgrading of lignins, that are byproducts of the biomass pretreatment and extraction methods, will enable the maximization of yields from biomass conversion to fuels and value-added products.