A Bi2WO6-based hybrid heterostructures photocatalyst with enhanced photodecomposition and photocatalytic hydrogen evolution through Z-scheme process

A Bi2WO6-based hybrid heterostructure photocatalyst were fabricated by two step hydrothermal method. Bi2WO6 nanosheets with side length of 100-200 nm and thickness and about 20 nm thickness was homogeneously overcoated at the surface of CdS nanowires with an average diameter of 50 nm. The formation of hybrid heterostructures could efficiently enhanced the photocatalytic activity. The hybrid heterostructures photocatalyst of Bi2WO6/CdS achieved the highest photocatalytic H-2 evolution (1223 mu mol h(-1)g(-1)) under visible light irradiation which is much higher than the pristine CdS (602 mu mol h(-1)g(-1)). Furthermore, the photocatalytic pollutant decomposition efficiency of hybrid heterostructures was well promoted compare to Bi2WO6 and CdS. The role of main oxidative species in the photocatalytic process was confirmed by the active species trapping experiments. The experimental results concluded that the enhanced photocatalytic activity and photostability of hybrid heterostructures is mainly associated with the Z-scheme photocatalytic charge transfer of the photogenerated charge carriers. Based on the obtained experimental results and calculation, a precise Z-scheme mechanism was proposed and discussed, which was further evaluated by the electrochemical spectroscopic study of the prepared photocatalyst. The Z-scheme photocatalytic system bestows the Bi2WO6/CdS hybrid heterostructures with efficient reducibility, stability and excellent oxidizability. (C) 2018 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.