Photocatalytic Reforming of Lignocelluloses, Glycerol, and Chlorella to Hydrogen

Abstract

Bioethanol, biodiesel, and biogas have gained much attention as sustainable energy alternatives to petroleum-based fuels. Bioethanol production is the most typical method to provide liquid fuel. Recently cellulosic materials have been recognized as one of the promising sources for bioethanol, since they are not directly in competition with food sources. However, ethanol concentration is usually too low to separate by distillation at a low-energy cost. Gaseous H 2 is spontaneously isolated without operation to separate. Therefore, H 2 production is an economical approach to biofuels. Photocatalytic H 2 production over a Pt-loaded TiO 2 is initiated by the charge separation. Electrons reduce water to generate H 2, while holes oxidize hydroxide to hydroxyl radicals. Generally, the use of sacrificial agents remarkably accelerates the H 2 production since the hydroxyl radical is consumed by them. This chapter deals with the photocatalytic H 2 production (PR) using sacrificial water-soluble materials derived from lignocelluloses, lipids, and Chlorella. Lignocellulosic Italian ryegrass (2.00 g) was turned into H 2 (78.7 mg) through alkali treatment, hydrolysis, and PR processes. The PR process of glycerol (10.4 g) and methanol (11.3 g), which were by-products in biodiesel synthesis, formed H 2 (3.10 g). Dried Chlorella (10 g) was turned into H 2 (578 mg) by protease hydrolysis and PR.

Glycerol as a Superior Electron Source in Sacrificial H2 Production over TiO2 Photocatalyst

“…Generally, biomass reforming is started by the production of water-soluble materials from biomass through biological treatment as well as chemical reaction [17,18]. The resulting water-soluble materials (saccharides, amino acids) are converted to biofuels such as ethanol, methane, and hydrogen through various catalytic reactions in aqueous solution.…”