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

Abstract

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.