HYDROGEN PRODUCTION VIA ALKALINE HYDROTHERMAL TREATMENT OF CELLULOSE: DEVELOPMENT OF NANOFIBER CATALYSTS AND MODEL SUBSTRATES

摘要

We have been developing a small rural or farm-scale biorefining system that can convert cellulosic biomass and/or farm wastes into hydrogen and electricity. In particular, we focus on the development of innovative pretreatment procedures to incorporate catalysts into biomass and cost-effective catalysts for the alkaline hydrothermal treatment. Compared to conventional gasification and pyrolysis, the alkaline hydrothermal treatment is a less-studied method of biomass conversion but with great potential, and the development of cost-effective pretreatments and catalysts becomes critical to make the process economically viable. While we have been developing economic physical and chemical routes to incorporate catalysts into well-characterized cellulose substrates, one-dimensional materials such as nanofibers also have been investigated to support catalytic nanoparticles to maintain the high surface area to volume ratio while inhibiting the aggregation phenomenon. We synthesized inorganic (silica, alumina, zirconia) nanofibers where the Ni nanocatalyst location is tuned toward the surface of the nanofiber. The resulting nanofibers were applied as a catalytic system for the alkaline hydrolysis of glucose to selectively produce hydrogen with minimal carbon monoxide or dioxide byproducts. Meanwhile, we prepared the model cellulose substrates where their microstructure such as the degree of polymerization, degree of crystallinity, and surface area was independently controlled by varying the binary solvent and spinning conditions.