Enhanced Synergistic performance of ZnO@BiOX (X=Cl, Br, I) heterojunction for photocatalytic degradation of emerging pollutants under visible light

In this work, we study the influence of the proportion and halogen type present in heterojunctions of zinc oxide and bismuth oxyhalides ZnO@BiOX (Where X=Cl-, Br-, I- and several binary combinations of them) on the photocatalytic activity in the degradation of rhodamine-B (Rh-B) under visible light, as well as in two important emergent contaminants resorcinol and sulfadiazine. The materials were synthesized by a solvothermal process at 130 degrees C, starting from ZnO nanoparticles and BiOX precursors (Bi+ and X=Cl-, Br-, I- ions). It was found that the best combination of halogens was 75% Br- and 25% Cl-(ZnO@BiOBrCl bromine-chlorine ratio 3:1) forming a Z-type heterojunction with a time constant of tau = 5.6067 min (kappa = tau(-1) = 0.1784 min(-1)) in the degradation of Rh-B (C-0 = 30 ppm, V-Rxn = 250 mL). The same composite degraded totally resorcinol in 250 min, and 85.2 % of sulfadiazine in 150 min.