The limited hydrothermal stability of many supported metal catalysts is a major concern for the development of heterogeneously catalyzed processes for biomass conversion. In hot liquid water alumina supports are converted into boehmite, which results in losses of surface area, acid site concentration, and metal dispersion. The formation of boehmite starts by the reaction of water molecules with the hydroxyl groups of alumina. This transformation can be prevented in the presence of polyols because these compounds chemisorb to surface hydroxyl groups on alumina. The resulting layer of carbonaceous deposits inhibits hydrolytic attack, and the high surface area of the catalyst is retained. The stabilizing effect becomes more pronounced for larger polyols (e.g. sorbitol) because these compounds can form additional bonds with the surface. Although some blockage of metal sites is observed, the sufficient fraction of the metal surface area remains accessible to convert reactants.

Increased stability of Pt/Al<sub>2</sub>O<sub>3</sub> catalysts in aqueous polyol solutions

244th National Meeting (2012)

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Increased stability of Pt/Al2O3 catalysts in aqueous polyol solutions

Increased stability of Pt/Al₂O₃ catalysts in aqueous polyol solutions