Facile assembly and excellent elimination behavior of porous BiOBr-g-CN heterojunctions for organic pollutants.

Photocatalysis can be an effective technique for eliminating organic contaminants from water. In this study, BiOBr flower-spheres coupled with porous graphite carbon nitride (g-CN) were synthesized by controlling the dosage of cetyltrimethylammonium bromide (CTAB). Various characterization techniques were then applied to elucidate the structure-performance relationships of the resulting heterojunction photocatalysts in degrading organic dyes. Experimental results established an optimal molar ratio for KBr to CTAB of 5:1. Benefiting from a remarkable porous structure and tight coupling between porous g-CN and BiOBr, the optimal BiOBr-g-CN(2%) exhibited enhanced visible light absorption capability and promoted the separation of photoinduced carriers. Total removal efficiency for rhodamine B (RhB, 25.0 mL, 20.0 mg L) reached 87% within 30 min in the presence of BiOBr-g-CN(2%) (20.0 mg) (i.e., 1.51 μmol (g min)), which is superior to the performance of BiOBr (72%) (i.e., 1.25 μmol (g min)), g-CN (21%) (i.e., 0.37 μmol (g min)). Furthermore, the photocatalytic reaction rate constant over the optimal heterojunction was 0.034 min, which is significantly larger than those of porous g-C3N4 (0.003 min) and BiOBr (0.015 min). Moreover, this type II heterojunction showed good universality for other organic dyes (such as methyl violet, methylene blue, and crystal violet), highlighting a promising potential role in the elimination of environmental pollutants.