“…Therefore, it has received wide attention in different emerging fields such as energy storage, environmental remediation, and catalysis. , Coffee residues, which can be produced in coffee shops all over the world, are usually abandoned or landfilled. In contrast to other biochar precursors, coffee residues are rich in starch, vegetable oils, sugars, and proteins and could be used as a promising biomass for the synthesis of heteroatom-doped biochar composites. − However, biochar produced by a direct pyrolysis method generally has a low BET surface area, and a post-treatment activation procedure is usually required. , Due to the pollution-free nature of the resulting biochar, significant preference has been given to the use of H 3 PO 4 as the activating agent. , …”