Synergizing black gold and light: A comprehensive analysis of biochar-photocatalysis integration for green remediation

• The history, morphology, classification, properties, synthesis, and applications of biochar are deeply explored. • The photocatalysis and photocatalytic materials are extensively investigated. • The relationship between photocatalysis and biochar is carried out. • The latest trends, opportunities, and roadblocks of biochar-based photocatalysts (BBPs) are explored. Biochar is a porous, high-surface-area, black carbon-rich product that offers a cost-effective and environmentally friendly option to replace conventional charcoal. However, its specific structure and limited biodegradability pose challenges for its widespread applications. Photocatalysis is suggested as an alternative approach to harness solar energy and transform it into solar fuels. Interestingly, nanomaterials-based photocatalysts with tailored energy band properties and non-toxic characteristics, high surface areas, enhanced stability, and tunable pore sizes, have gained attention for their potential in diverse applications. Therefore, existing research on biochar-based photocatalysis systems (BBPs) aims to address different environmental issues. Interestingly, BBPs offer benefits such as excellent electrical conductivity, versatile functional groups, large surface area, and multiple surface-active sites, promoting high charge mobility, electron reservoir, superior charge separation, and small bandgap. This review provides a comprehensive overview of BBPs developments, including synthesis methods and properties. The fusion of BBPs is used in CO 2 conversion, photocatalytic H 2 generation, CO 2 reduction, pollutants, dyes, and pharmaceutical degradation. Although the intermarriage of BBPs has potential benefits, their effectiveness may be compromised when modified photocatalysts are incorporated, which may negatively influence carrier generation efficiency and overall performance. Therefore, there is empty room for further research on their physical properties, effectiveness, long-term stability, and reusability of BBPs.