Artículos SCI

Catalytic hydrodeoxygenation (HDO) is a critical technique for upgrading biomass derivatives to deoxygenated fuels or other high-value compounds. Phenol, guaiacol, anisole, p-cresol, m-cresol and vanillin are all monomeric phenolics produced from lignin. Guaiacol is often utilised as a model lignin compound to deduce mechanistic information about the bio-oil upgrading process. Typically, a source of H2 is supplied as reactant for the HDO reaction. However, the H2 supply, due to the high cost of production and additional safety precautions needed for storage and transportation, imposes significant economic infeasibilities on the HDO process's scaling up. We investigated a novel H2-free hydrodeoxygenation (HDO) reaction of guaiacol at low temperatures and pressures, using water as both a reaction medium and hydrogen source. A variety of Ni catalysts supported on zirconia/ graphene/with/without nitrogen doping were synthesised and evaluated at 250 degrees C and 300 degrees C in a batch reactor, with the goal of performing a multi-step tandem reaction including water splitting followed by HDO. The catalysts were characterised using H2-TPR, XRD, TEM and XPS to better understand the physicochemical properties and their correlation with catalytic performance of the samples in the HDO process. Indeed, our NiZr2O/Gr-n present the best activity/selectivity balance and it is deemed as a promising catalyst to conduct the H2-free HDO reaction. The catalyst reached commendable conversion levels and selectivity to mono-oxygenated compounds considering the very challenging reaction conditions. This innovative HDO approach provides a new avenue for cost-effective biomass upgrading.

Biofuels upgrading gathering momentum in view of the gradual depletion of fossil fuels and the pursuit of renewable energy sources to mitigate global warming. Hydrodeoxygenation (HDO) is a key reaction in the upgrading of bio-oil to produce hydrocarbon fuels or high-value chemicals. Oxygen removal in bio-oil increases its calorific value, improve thermal and chemical stability, reduce corrosiveness, etc., making the upgraded biooil suitable as a fuel or blending fuel. However, the dependence on high-pressure hydrogen is a serious disadvantage, as it is an expensive resource whose use also poses safety concerns. In this scenario, we propose a pioneering route for model biomass compounds upgrading via H2-free HDO. Herein we have developed multifunctional catalysts based on Ru and ceria supported on carbon able conduct the hydrodeoxygenation reaction using water as hydrogen source. We found that cerium oxide improves ruthenium metallic dispersion and the overall redox properties of the multicomponent system leading to enhanced catalytic performance. Along with the successful catalytic formulation we identify 300 degrees C as an optimal temperature validating the H2-free HDO route for bio-compounds upgrading.