Recent developments in lignocellulosic biomass catalytic fast pyrolysis: Strategies for the optimization of bio-oil quality and yield

Catalytic fast pyrolysis (CFP) is an attractive approach to convert biomass to high-quality bio-oil through the deoxygenation of pyrolysis vapors in the form of H2O, CO, and CO2, However, the deoxygenation process comes at the expense of bio-oil yield. This review begins with recent progress on lignocellulosic biomass pyrolysis chemistry and techniques, and then focuses on the latest improvements to the design of advanced catalysts and novel CFP processes. It was found that basic metal oxides (e.g., MgO and CaO) are promising alternative catalysts to zeolites (such as ZSM-5) with respect to the preferred decarboxylation reaction, which merits additional investigation on their structure-function relationships in the future. Additionally, catalytic co-pyrolysis of biomass with waste plastics or waste tires over zeolites is an attractive approach from the viewpoint of preferred dehydration reactions and the high-value utilization of solid wastes. However, the physicochemical properties of the catalysts should be further adjusted. Furthermore, in spite of many interesting results reported in the literature, quantitatively analysis and uniform data presentation format is necessary for the further development of CFP techniques.