“…As mentioned above, the structure of g‐C 3 N 4 is flexible due to its polymeric feature, which favors the formation of heterojunctions with close interconnection between g‐C 3 N 4 and various semiconductors. A large number of semiconductors have been coupled with g‐C 3 N 4 to form semiconductor–semiconductor heterojunctions, including metal oxides (e.g., TiO 2 , ZnO, WO 3 , Cu 2 O, In 2 O 3 , Fe 2 O 3 , MoO 3 , CeO 2 , SnO 2 , and Nb 2 O 5 ), multi‐component oxides (e.g., ZnWO 4 , ZnFe 2 O 4 , Zn 2 GeO 4 , SrTiO 3 , In 2 TiO 5 , DyVO 4 , GdVO 4 , LaVO 4 , YVO 4 , NaTaO 3 , NaNbO 3 , HNb 3 O 8 , H 2 Ta 2 O 6 , and H 3 PW 12 O 40 ), metal oxynitrides (e.g., TaON, and ZnGaNO), metal chalcogenides (e.g., CdS, CuInS 2 , and CuGaSe 2 ,), bismuth‐based compounds (e.g., BiPO 4 , BiVO 4 , Bi 2 WO 6 , BiOCl, BiOBr, BiOI, Bi 2 O 2 CO 3 , and Bi 5 Nb 3 O 15…”