“…Semiconductor-based photocatalysis technology is regarded as a new entryway to overcoming the huge consumption of energy. − The key difficulty is to look for stable photocatalysts because of their high efficiency and low cost. Though a series of photocatalysts like metal oxides (sulfides, nitrides), − metal–organic framework material, , and Bi-based photocatalysts have been designed, , nevertheless, the unsatisfactory light absorption, rapid charge recombination, and limited active sites greatly restrict the efficient photocatalytic H 2 evolution, CO 2 reduction, and pollutant removal . Recently, graphitic carbon nitride (CN) has been confirmed as an earth-abundant visible-light photocatalyst due to its outstanding layered structure, better chemical and thermal stability, and applicable band gap. , Nevertheless, the bulk CN obtained by traditional thermal polymerization exhibits inherently limited photocatalytic performance due to its certain intrinsic drawbacks, such as the incomplete absorption of visible light, insufficient surface-active site, and rapid recombination of photogenerated hole–electron pairs. − In particular, the strong exciton effect from the Frenkel excitons interaction may hinder the dissociation of singlet exciton and is often ignored. − Free charge carriers will compete against neutral excitons during a photocatalytic reaction. , How to obtain a sufficient quantity of charge carriers via the dissociation of excitons into electrons and holes is still a vital challenge.…”