Heterojunction semiconductor g-C3N4/BiVO4 with an enhanced photocatalytic activity based on the effective chemical bonding

Graphitic carbon nitride (g-C3N4)/bismuth vanadate (BiVO4) heterojunctions were synthesised by a facile solvothermal approach. High-resolution transmission electron microscopy images demonstrated an close contact interfacebetween g-C3N4 and BiVO4 in heterojunctions had formed. X-ray diffraction, X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy results revealed that a chemical coupling between Bi and C atom occurred in heterojunctions. The photocatalytic degradation efficiency of malachite green (MG) in an aqueous phase under visible-light irradiation was enhanced effectively by chemically coupled g-C3N4/BiVO4 heterojunction. The photocatalytic efficiency of g-C3N4/BiVO4 heterojunction is almost 5.3, 4.9 and 3.1 times higher than those of individual g-C3N4, BiVO4 and the two mixture sample mechanically, respectively. The remarkable improvement of photocatalytic performance should be ascribed to the enhancement of absorptivity for dyes, an extended photo-response range and the formation of Z-scheme principled g-C3N4/BiVO4, which can lead to more effective photo-excited electron transfer and large suppressing recombination of photo-generated electron-hole pairs.