A facile fabrication of Br-modified g-C3N4/rGO composite catalyst for enhanced visible photocatalytic activity towards the degradation of harmful dyes

In this study, bare g-C3N4, g-C3N4/rGO and Br-modified g-C3N4/rGO catalysts were synthesized by a simple hydrothermal method. The synthesized catalysts were analyzed by XRD, FTIR, Raman, HR-SEM, TEM, BET, UV-DRS, PL and EIS techniques. The photocatalytic performance of synthesized catalysts was evaluated towards the decolourisation of Reactive Blue-19, Methyl Orange and Rhodamine-B dyes under visible light irradiation. In comparison with bare g-C3N4 and g-C3N4/rGO catalysts, the Br modified g-C3N4/rGO catalyst showed superior photocatalytic performance. The PL spectra of synthesized catalysts reveal that Br modified g-C3N4/rGO catalyst has a lower rate of electron hole-pair recombination when compared to bare g-C3N4 and g-C3N4/rGO catalysts, which leads to enhanced photocatalytic activity. The stability of the most active catalyst was analyzed by recyclability test. The major influences of photogenerated holes (h(+)) followed by O-center dot(2)- radicals and (OH)-O-center dot radicals were observed on the photocatalytic degradation of dyes by radical trapping experiment over Br modified g-C3N4/rGO.