Enhancement of Biomass Hydrolysis by HSiW/Graphene Catalyst

Miri Klein, Bar- Ilan University, Ramat Gan, Israel

Demand for alternate transportation fuels is continuously increasing. Supply of fossil fuels is limited.  Bioethanol, produced from the fermentation of sugars, is a potential biofuel produced currently. Glycogen is an upcoming alternative feedstock for the production of glucose.

Silicotungstic acid (HSiW) was deposited on graphene by an ultrasound-assisted procedure. The catalyst (HSiW/G) was characterized using a variety of physico-chemical methods. Homogeneous distribution of HSiW on the surface of graphene was achieved. XRD, Raman and SEM studies indicated that the graphene layers are not damaged during the sonochemical synthesis of the HSiW/G catalyst.

The hydrolysis of glycogen was performed with HSiW/G catalyst by hydrothermal process. The yield of glucose (66 wt. %) obtained was about 8 times higher than that obtained with the same amount of bare HSiW. Stability of the HSiW/graphene even after 3 repeated uses was confirmed. The mechanism of the enhancement of catalytic activity was discussed in terms of special interaction between the graphene support and HSiW and also by the appearance of hydrophobic cavities on the surface of graphene. The formation of these cavities facilitate the anchoring of glycogen to the catalyst surface and promote the attack of protons that leads to selective, rapid, and efficient hydrolysis.