Remarkably enhanced photocatalytic activity of ordered mesoporous carbon/g-C₃N₄ composite photocatalysts under visible light.

Ordered mesoporous carbon/g-C3N4 (OMC/g-C3N4) composites with efficient photocatalytic activity under visible light irradiation were prepared by a facile heating method. The as-prepared OMC/g-C3N4 composites were thoroughly characterized by X-ray diffraction, Fourier transform infrared spectroscopy, elemental analyses, transmission electron microscopy with energy dispersion X-ray spectroscopy, N2 adsorption-desorption analysis, UV-vis diffuse reflectance spectroscopy and photoluminescence spectroscopy. The photocatalytic activities were evaluated by degrading Rhodamine B dye, and OMC/g-C3N4 composites exhibited much higher photocatalytic activities than pristine g-C3N4. Moreover, the catalysts retained good stability and the photodegradation efficiency hardly changed after five cycles. The degradation rate of the OMC/g-C3N4 photocatalyst was almost 10 times as high as that of the pristine g-C3N4, which indicated that OMC played an important role in the remarkable improvement of photocatalytic activity. The significant enhancement in photodegradation activity over the OMC/g-C3N4 catalyst could be ascribed to the combined effects coming from the enhanced visible light adsorption, enriched adsorption of the dye on the catalyst and subsequent efficient separation of photogenerated electrons and holes. In addition, a possible mechanism for the photodegradation process was proposed on the basis of active species scavenging experiments.