Selecting Catalysts for Pyrolysis of Lignocellulosic Biomass

Abstract

The pyrolysis of lignocellulosic biomass is a promising technology for obtaining renewable chemicals and fuels to replace fossil-based products. However, due to the complexity of the lignin, cellulose and hemicellulose molecules, a large variety of compounds are often formed, making commercial implementation difficult. The use of a catalyst during reactions has been recognized as one of the major improvements in pyrolysis, allowing the production of selected compounds. Moreover, the large number of available catalysts opens up a wide range of possibilities for controlling the reaction network. Zeolites, hierarchical zeolites, alkali and alkaline earth oxides, transition metals and carbonaceous materials, among others, have been investigated in the pyrolysis of a variety of biomasses. In addition, bifunctional catalysts play a role in pyrolysis, as well as the addition of plastics as hydrogen donors. This review aims to present and discuss in detail state-of-the-art catalytic pyrolysis, focusing on the relationships between the properties of the catalysts and the obtained products. A guideline for selecting catalysts for lignocellulosic biomass is also provided.