Using polyfurfuryl alcohol to improve the hydrothermal stability of mesoporous oxides for reactions in the aqueous phase

Hydrodeoxygenation (HDO) of bio-oils derived from the pyrolysis of woody biomass is required to improve the stability and heating value of the liquid hydrocarbon products. Since pyrolysis produces bio-oils having up to 30 vol% water, HDO catalysts must not only be active and selective, but also stable under hydrothermal conditions associated with HDO upgrading. We investigated the effect of carbon coatings on a variety of silica, mixed zirconia-silica oxides and alumina. Surface area and porosity changes from exposure to controlled steaming conditions were used to evaluate the effectiveness of carbon coating on support stability. Systematic studies of the effects of the composition and structure of the carbon precursor, the inclusion of a zirconium modifier, the carbon loading and carbonization conditions led to the development of highly stable carbon modified zirconium silicate and mesoporous alumina supports that substantially maintain pore size distribution and surface area after steaming at 493 K with 23 bar of steam pressure.