The facile synthesis and enhanced photocatalytic activity of a graphitic carbon nitride isotype heterojunction with ordered mesopores

Abstract

In order to improve the photocatalytic activity of graphitic carbon nitride, we prepared a g-C₃N₄ isotype heterojunction with ordered mesopores through simple one-step calcination. Ordered mesoporous structures were prepared by directly condensing uniform mixtures of precursors and an SBA-15 sacrificial template. After the removal of SBA-15, the physical and chemical properties of the resulting samples were characterized via XRD, TEM, XPS, FT-IR, UV-vis, PL and N₂ physical adsorption studies. Significantly, the samples serve as more efficient photocatalysts for the removal of methyl orange than pure g-C₃N₄ and a g-C₃N₄ isotype heterojunction without ordered mesopores. The optimum photocatalytic activity of DUPG2 is almost 3 times higher than bulk g-C₃N₄. After irradiation for 120 min under visible light, it gives a degradation rate of 82% with good stability. The enhanced photocatalytic activity could be attributed to the fact that the isotype heterojunction and ordered mesopores accelerate the separation of photogenerated electron–hole pairs and enhance the efficiency of visible light utilization.