Liquid phase reforming of woody biomass to hydrogen

Abstract

This work concentrates on the production of H2 directly from raw biomass through liquid phase reforming in the presence of a liquid base and a solid catalyst. Both precious metal and base metal catalysts were found to be active for the liquid phase hydrolysis and reforming of wood. Pt-based catalysts, particularly Pt–Re, were shown by atomistic modeling to be more selective toward breaking C–C bonds, resulting in a higher selectivity to hydrogen versus methane. Ni-based catalysts were found to prefer breaking C–O bonds, favoring the production of methane. The results showed that at a constant wood concentration, increasing the concentration of base (base to wood ratio) in the presence of Raney Ni catalysts resulted in greater selectivity toward hydrogen. The amount of wood converted to gas was lower due to increased production of undesirable organic acids from the wood at higher base concentrations. It was shown that by modifying Ni-based catalysts with dopants, it was possible to reduce the base concentration while maintaining the selectivity toward hydrogen and increasing wood conversion to gas versus organic acids.