Potential application of a porous graphitic carbon nitride as an organic metal-free photocatalyst for water splitting

摘要

The new carbon nitride material (C2N-h2D) has been synthesized experimentally by Mahmood et al. (Nature Communications, 2015, 6, 6486), however, there is still no study regarding its application as a photocatalyst for water splitting. Herein, we studied the electronic structures and optical properties of C2N-h2D, and explored the possibility of C2N-h2D as an active photocatalyst for hydrogen generation through water splitting. On the basis of our calculation results, the C2N-h2D is suggested to be a direct band gap semiconductor. The positions of the CBM and the VBM are ideal with respect to the standard water redox potentials. More importantly, C2N-h2D can effectively absorb visible light, indicating a promising photocatalyst for water splitting. In order to absorb more visible light, we further analyzed a series of methods, such as applying tensile, multilayer stacking and doping with boron, oxygen, phosphorus and sulfur. The band arrangements and optical absorption properties of the doped materials reveal that the boron and oxygen doped C2N-h2D can effectively extend the range of light absorption, and therefor enhance the photocatalytic efficiency. This makes C2N-h2D having more practical value, and makes the experiment of Mahmood being more meaningful.