Enhanced photocatalytic activity of mesoporous carbon/C₃N₄ composite photocatalysts

The C₃N₄ as a cheap and clean photocatalyst shows suitable band gap to splitting water and spectral response. However the poor conductivity of C₃N₄ limits the photocatalytic hydrogen evolution rate. The combination of C₃N₄ and high conductivity materials will enhance the separation of photo-generated carriers and thus enhance the photocatalytic activity. As many carbon materials have been tried, the mesoporous carbon should be a good candidate to solve this problem.

A photocatalytic system with C₃N₄ and mesoporous carbon has been designed to test the photocatalytic performance of both the photocatalytic hydrogen evolution and the photocatalytic degradation of methylene blue. The results of EPR, EIS and PL spectra were given to further understand the photo-generated carrier and its transfer.

The enhancement of the highest hydrogen evolution rate is 48% from 69 to 102 μmol/h by mesoporous carbon/C₃N₄ sample. The existence of small amount of mesoporous carbon can facilitate the photogenerated carrier separation, thus enhancing the photocatalytic performance. In the meantime, the introduction of mesoporous carbon into C₃N₄ is beneficial for improving electron delocalization and conduction electrons and increasing the optical absorption.