Bi2WO6-wrapped 2D Ni-MOF sheets with significantly improved photocatalytic activity by a direct Z-scheme electron transfer

Abstract

Constructing Z-scheme heterojunction is considered to be a promising strategy to isolate photogenerated carriers and boost the activity of the photocatalysts. Here in, a novel Z-scheme Bi2WO6/Ni-MOF heterojunction with intimate interface was constructed via wrapping flowerlike Bi2WO6 on 2D Ni-MOF sheets. The resultant Bi2WO6/Ni-MOF heterojunction displayed superior photocatalytic performance with respect to methylene blue degradation under visible light illumination. When the content of Ni-MOF was 20 wt%, the Bi2WO6/Ni-MOF heterojunction achieved the highest activity, which was 24.0 and 6.4 folds that of the pristine Ni-MOF and Bi2WO6, respectively. The superior degradation performance was caused by the formation of a direct Z-scheme heterostructure between Ni-MOF and Bi2WO6, which boosted the separation of photoinduced carriers. The principal active species and possible photocatalytic mechanism were also explored. This study provides a pathway to design and fabricate efficient Z-scheme photocatalysts for environmental remediation.