A two-dimensional Aurivillius oxide for enhanced solar energy driven hydrogen evolution and waste water treatment.

Bi 2 WO 6 has attracted extensive attention in photocatalysts in recent years as a typical Aurivillius oxide. However, it suffers from severe electron-hole recombination due to the large charge transfer distance from bulk to surface. Unfortunately, strong chemical bonds between the neighboring layers in Aurivillius oxides lead to difficulties in the construction of 2D materials. Here, a facile NaBH 4 -assisted hydrothermal method is developed to construct 2D Bi 2 WO 6 nanosheets with adjustable thickness from 4.03 to 1.51 nm and O vacancies density (named as BWO-x, x = 15, 30, 45, 60). By balancing the thickness and the O vacancy density in the nanosheets, the charge separation efficiency can be tuned and consequently, the photocatalytic activity can be optimized, leading to over 11 times enhancement in photocatalytic hydrogen evolution. Furthermore, the best performed nanosheets demonstrate universality in dye polluted water treatment. Nearly 100% degradation can be reached after only 5, 50, and 30 min with degradation rate constant of 29.73, 3.21, and 6.62 min−1g−1 for Rhodamine B, methyl orange, and methylene blue, respectively. This work provides a comprehensive approach to produce ultrathin 2D nanosheets of Aurivillius photocatalysts for enhanced charge separation and photocatalytic activity. • Ultrathin 2D Bi 2 WO 6 nanosheets have been constructed. • Improved charge separation has been achieved in the ultrathin 2D BWO nanosheets. • The 2D BWO nanosheets exhibit enhanced photocatalytic H 2 evolution and dye degradation. • This work provides a comprehensive approach to produce ultrathin 2D nanosheets of Aurivillius Oxides. [ABSTRACT FROM AUTHOR]