Abstract
The increasing concentration of atmospheric CO2 has intensified the search for sustainable technologies capable of converting this greenhouse gas into valuable fuels and chemicals. Among the available approaches, thermocatalytic, photocatalytic, and electrochemical CO2 reduction have emerged as key strategies for carbon valorisation. In this regard, biochar-derived materials have recently attracted growing attention due to their renewable origin, tunable porosity, rich surface chemistry, and ability to support active catalytic sites. These properties enhance CO2 adsorption, activation, and charge-transfer processes, making biochar a promising platform across multiple CO2 reduction pathways. This review provides a critical overview of recent advances in thermocatalytic, photocatalytic, and electrochemical CO2 reduction using biochar-based materials, highlighting the relationship between material properties and catalytic performance. Particular attention is given to integrated capture-conversion systems, where biochar enables the coupling of CO2 adsorption and catalytic transformation within a single material architecture. Current challenges and future research directions are discussed to support the development of scalable biochar-based technologies for sustainable carbon utilisation.