Selective breaking of hydrogen bonds of layered carbon nitride for visible light photocatalysis

Abstract

Two remarkable features were created by selectively breaking hydrogen bonds existing in the C-N covalent bonds-dominated intralayer framework of layered carbon nitride. One is the increased band tails or localized states close to the band edges as a result of the destruction of intralayer long-range atomic order and loss of partial nitrogen atoms. The other is the abundant pores formed throughout the whole particles as a result of volume shrinkage with the breaking of hydrogen bonds. These abundant pores subsequently promote the transfer of electrons to reach the lateral surface of the pores by providing additional reductive reaction sites. As a consequence of these favorable changes in improving all three basic processes of photocatalysis, the carbon nitride with an optimized breaking of hydrogen bonds gives a significantly enhanced photocatalytic hydrogen generation activity under visible light. These results suggest that the number of the reductive reaction sites of the carbon nitride with broken hydrogen bonds is greatly increased with the abundant lateral edges/surfaces of the pore walls as additional reductive reaction sites