Biochar has emerged as a multifunctional material with significant potential in bioenergy conversion and utilization, prompting recent innovations aimed at enhancing its production efficiency, properties, and applications. One notable innovation is the development of catalytic fast pyrolysis techniques to produce engineered biochar with tailored surface functionalities. Traditional pyrolysis produces biochar alongside bio-oil and syngas, but catalytic fast pyrolysis incorporates catalysts such as transition metal oxides or zeolites into the biomass feedstock or reactor bed. The presence of catalysts modifies the thermal decomposition pathways, promoting deoxygenation and aromatization reactions, which not only improve the yield and quality of bio-oil and syngas but also result in biochar with enhanced porosity and active sites (e.g., increased acidic or basic functional groups). These engineered biochars exhibit superior performance in