Synthesis of direct Z-Scheme Bi3NbO7/BiOCl photocatalysts with enhanced activity for CIP degradation and Cr(VI) reduction under visible light irradiation

Direct Z-scheme Bi3NbO7/BiOCl composite photocatalytic materials were fabricated via a facile hydrothermal method. The photocatalytic activity of the synthesized catalyst samples for Cr(VI) reduction and CIP degradation was investigated under visible light irradiation. The Bi3NbO7/BiOCl-2 composite showed the highest photocatalytic performance. Its apparent rate constant for photocatalytic degradation of CIP was 5.1 and 14.3 times as that of BNO and BiOCl, respectively. And the apparent rate constant for photocatalytic reduction of Cr(VI) was 33.2 and 17.6 times as that of BNO and BiOCl. The superior activity was chiefly ascribed to the Z-scheme heterojunction formed between Bi3NbO7 and BiOCl, which effectively promoted the efficiency of carrier separation and migration. Furthermore, the prepared BNO/BiOCl-2 composite photocatalyst showed stable activity in four photocatalytic cycling experiments of CIP and Cr(VI). This work provided a good example for further design and preparation of other Z-scheme photocatalysts with high performance for the remediation of both organic and heavy metal pollutants.