Synergetic effect of g-C3N4/ZnO binary nanocomposites heterojunction on improving charge carrier separation through 2D/1D nanostructures for effective photocatalytic activity under the sunlight irradiation

摘要

The heterojunction between the two different semiconductors shown to increase the photocatalytic activity due to their ability in improving the photo-generated electron-hole pairs separation. Hence designing and synthesizing such heterojunctions employing different semiconducting materials to improve the photocatalytic efficiency using various methods have gained importance. For this purpose graphitic like carbon nitride (g-C3N4) is a hopeful photocatalytic material for environmental remediation but its photogenerated charge carriers recombination rate limits g-C3N4 for practical applications. Hence, in the present work we synthesized heterojunction of g-C3N4/ZnO binary nanocomposites in 2D/1D by sonication assisted hydrothermal method. X-ray diffraction analysis confirms the formation of g-C3N4/ZnO binary nanocomposites. Transmission electron microscope analysis shows that the binary nanocomposites consists ZnO rods coupled with sheet like structure of g-C3N4. The band gap of g-C3N4 is 2.67 eV; however, the g-C3N4/ZnO binary nanocomposites shifts the band gap to 2.9 eV. Photoluminescence spectral analysis evidently shows the recombination rate of electron-hole pairs in the g-C3N4/ZnO binary nanocomposites is effectively reduced due to the formation of the heterojunction. The photoelectrochemical analysis shows that g-C3N4/ZnO binary nanocomposites enhance the photocurrent to 1.5 mu A and effectively separate the electron-hole pairs when compared with that of bare ZnO and g-C3N4. Hence, the g-C3N4/ZnO binary nanocomposites effectively enhanced RhB dye degradation to 99% for 20 min and enhanced the 4-chlorophenol degradation to 90% for 40 min. under the sunlight irradiation.