Understanding Pt-Re Catalysts Used for Aqueous Phase Reforming of Biomass

Aqueous phase reforming (APR) is a process by which a substrate molecule is reacted in aqueous phase to produce hydrogen. When applied to biomass, this technique can be used to produce hydrogen from oxygenated hydrocarbon such as glucose, glycerol and acetic acid. Extensive research in the literature has shown the efficacy of Pt-Re bimetallic catalysts for this reaction for various substrate molecules. However, not much characterization is done in understanding this catalyst with respect to APR. Hence we studied the influence of supports, acidity, Pt:Re ratio on the APR process. We studied this using CO-TPD, TPRS, pyridine –DRIFTS and some batch reactions. We have shown that CO-Metal bonding is stronger on silica than on zirconia supports. Also water addition strengthens this bonding. Py-DRIFTS showed the emergence of Brønsted acidity with water addition. This acidity seems to arise from Pt more than from Re and the support. Lewis acidity was seen consistently on the surfaces. More work is underway including a correlation between the observed properties and APR product distribution.