Design of Bifunctional Solid Catalysts for Conversion of Biomass-Derived Syngas into Biofuels

Abstract

Biomass resources can be thought of as an important source of syngas (CO + H2). The conversion of the biomass-derived syngas (bio-syngas) into biofuels represents a carbon dioxide-neutral route for the production of substitute of the petroleum-derived fuels. Fischer–Tropsch synthesis (FTS) is by far the most effective approach to convert syngas into biofuels. However, FTS produces unselectively normal aliphatic hydrocarbons with a broad distribution of carbon numbers. To selectively produce biofuels, bifunctional FTS catalysts composed of an FTS-active metal and an acidic zeolite can be used. Such catalysts are capable of narrowing down the distribution of the products into the liquid fuel fraction by means of hydrocracking, isomerization, and hydrogenolysis. At the beginning of this chapter, the pathways of biofuel production from lignocellulosic biomass and the processes involved in transforming lignocellulosic biomass to bio-syngas are introduced. Then, research activities on converting syngas into biofuels over bifunctional FTS catalysts are described and ideas for catalyst engineering, catalyst structure, and catalytic outcome are highlighted. This chapter describes some of the selectivity control strategies that can be adopted with bifunctional catalysts so that restrictions given by classical Anderson–Schulz–Flory distribution can be overcome and industrialization can be realized.