Synthesis and High Visible Light Photocatalytic Activity of Ternary Brookite-g-C₃N₄-BiOBr Composite

Brookite TiO2 was synthesized by a hydrothermal method, g-C3N4 was prepared by a pyrolytic method, brookite/g-C3N4 composites were prepared by a calcining method, and brookite/g-C3N4/BiOBr ternary composites were prepared by loading BiOBr on the surface of brookite/g-C3N4. XRD and XPS analysis of the composites confirmed the formation of brookite TiO2/g-C3N4/BiOBr. SEM and TEM results confirmed the as-prepared composites were nanosized. The optimum loading amount of BiOBr was 30%. The photocatalytic results showed that the brookite/g-C3N4/30%BiOBr composites degraded rhodamine B completely under visible light irradiation. The degradation ratio of brookite/g-C3N4/30%BiOBr toward rhodamine B was nearly 100% for 2[Formula: see text]h, which was much higher than that of brookite TiO2 and brookite/g-C3N4 catalysts. The reason for the improvement of photocatalytic activity might be because the composites promoted the formation of superoxide radicals and the separation efficiency of photogenerated electron-hole pairs. The photocurrent density of the brookite/g-C3N4/30%BiOBr was about 10 times higher than that of pure brookite. In addition, the brookite/g-C3N4/BiOBr showed a good repeatablity of photocatalysis.