Research Projects

It is widely recognized that renewable energy feedstocks are essential for long-term economic and social stability. The consumption of fossil fuels increases levels of greenhouse gas emissions; CO2 levels have increased from 280 ppm in the 18th century to over 400 ppm as of 2016. Global average temperatures are expected to increase by 2-4 oC above pre-industrial levels by 2100. To overcome these concerns, 20% reduction in GHG emissions by 2030, a 20% renewable energy market share, and a 20% improvement in energy efficiency. In this context, replacing fossil-based fuels and chemicals with renewable energy feedstocks is a potential strategy for a sustainable society and economy. Lignocellulose is the most abundant renewable biomass feedstock, with an annual growth of 170 BT and it does not compete with food supplies because of its non-edible nature. It is composed of cellulose (30-50%), hemicellulose (20-35%) and lignin (15-30%). The conversion of cellulose and hemicellulose into fuels and chemicals has been extensively studied over the past few years. In contrast, lignin constitutes up to 30 wt.% of woody biomass, is highly underutilized due to its amorphous, complex polymeric structure. Lignin is only scalable renewable feedstock consisting of abundant aromatic chemicals derived from p-coumaryl, coniferyl and sinapylalcohols. Hence, lignin valorisation is a potential route to obtain useful aromatic compounds, which are key building blocks for the current chemical industry, thus reducing our dependence on fossil fuel-derived chemicals This project aims to develop an efficient one-pot process for conversion of lignocellulose biomass into useful chemicals using new multifunctional M-Ni/ZnO (M = Pd, Ru) catalysts. For this, ethanol is used as both the solvent for the fractionation of lignocellulose into solid (hemi)cellulose and liquid lignin oil as well as the H2-donor for the subsequent hydrogenolysis of lignin. The addition of Ni with Pd/Ru can adjust the degree of control in hydrogenolysis of lignin to selectively obtain phenolic chemicals due to the synergistic interactions of Ni with Pd, Ru and simultaneously minimizing the use of expensive noble metals. In addition, Ni species show a positive effect in catalysing hydrogen transfer from ethanol, facilitating in-situ hydrogen for lignin hydrogenolysis. Since Lewis acid sites of ZnO (Zn2+) can efficiently coordinate with β-O-4 bonds of lignin (most abundant linkage in lignin), shape-controlled ZnO materials (rods, spheres, and polyhedra), which may exhibit enhanced Lewis acid strength, play a key role in the cleavage of β-O-4 bonds during lignin hydrogenolysis to obtain maximum yields of phenolic chemicals. Therefore, the combination of Pd or Ru, Ni and shape-controlled ZnO with ethanol may show a promising effect in the fractionation of lignocellulose to obtain higher yields of lignin-derived phenolic chemicals and the valorisable solid (hemi)cellulose fraction in a single processing step.