A novel hollow-hierarchical structured BiWO with enhanced photocatalytic activity for CO photoreduction.

Converting CO into high-valued chemicals with sunlight is regarded as a promising way to solve the impending energy and environmental crisis. Development of efficient photocatalysts with suitable energy band gap, high stability and favorable structure is thus of very importance. Herein, a novel hierarchical BiWO photocatalyst assembled by BiWO nanosheets with a hollow and rod-shaped appearance has been developed via a facile hydrothermal process. Interestingly, we found that the hydrolysis of Bi(NO) in water can produce solid BiO(OH)(NO)·3HO microrods which can be transformed to hollow-hierarchical BiWO nanosheets by virtue of the Kirkendall effect. The developed BiWO nanosheets exhibit a 58 times higher specific surface area than that of bulk BiWO and a remarkable enhancement in electrochemical performance such as photocurrent and charge transfer. As a result, the hollow-hierarchical structured BiWO photocatalysts achieve a high CH yield of 2.6 μmol g h, 8 times higher than that of bulk BiWO. Moreover, the developed photocatalysts exhibit a high stability during the recycling experiments. This work may present a new strategy to attain hierarchical structured photocatalysts with high activity and stability toward CO reduction.