What is the best catalyst for biomass pyrolysis?

• The Role of alkali and alkaline earth metals in product distribution and deactivation of zeolites. • Carbon chemisorption or physisorption, metal particle encapsulation, and pore plugging. • Hierarchical zeolite/carbon/mesoporous silica synthesis and performance in biomass pyrolysis. • Preparation method of 3D biochar architecture and their surface morphology. • Development of advanced composites to overcome the major challenges in CP. Biomass pyrolysis has played an important role in environmental management by providing fuel and value-added chemicals from renewable resources. However, the variability in the properties of biomass necessitates the need for tunable catalysts that can favor specific reactions to target desirable compounds. Acid sites on catalysts are required for the cleavage of C C and C O bonds. While zeolite has been the most historically used catalyst for these processes, other materials such as silica and biomass-derived activated carbon have garnered the interest of researchers. All three types of catalysts have their strengths and weaknesses. In this study, the authors detail the synthesis and application of these catalysts in pyrolysis reactions. Advancements made in recent years were explored in detail, and key factors that influence the activity and stability of each type of catalysts are highlighted. The authors also provide their perspective on all three materials in terms of their potential to provide potential advancements in the field of catalytic pyrolysis. Finally, future research directions are indicated and summarized, based on results published in the literature with a particular focus on the development of composite to overcome the major challenges posed by the conventional catalysts.