Direct conversion of cellulose into polyols or H2 over Pt/Na(H)-ZSM-5

Abstract

The direct conversion of cellulose into polyols such as ethylene glycol and propylene glycol was examined over Pt catalysts supported on H-ZSM-5 with different SiO2/Al2O3 molar ratios. The Pt dispersion, determined by CO chemisorption and transmission electron microscopy (TEM), as well as the surface acid concentration measured by the temperature-programmed desorption of ammonia (NH3-TPD), increased with decreasing SiO2/Al2O3 molar ratio for Pt/H-ZSM-5. The total yield of the polyols, i.e., sorbitol, manitol, ethylene glycol and propylene glycol, generally increased with increasing Pt dispersion in Pt/H-ZSM-5. The one-pot aqueous-phase reforming of cellulose into H2 was also examined over the same catalysts. The Pt catalyst supported on H-ZSM-5 with a moderate SiO2/Al2O3 molar ratio and a large external surface area showed the highest H2 production rate. The Pt dispersion, surface acidity, external surface area and surface hydrophilicity appear to affect the catalytic activity for this reaction.