Construction of g-C 3 N 4 /S-g-C 3 N 4 metal-free isotype heterojunctions with an enhanced charge driving force and their photocatalytic performance under anoxic conditions

g-C 3 N 4 /S-g-C 3 N 4 metal-free isotype heterojunction catalysts with an enhanced charge driving force were prepared by a two step calcination method. The results indicate that this method can lead to a more efficient charge-carrier migration.