Vertical Growth of WO3 Nanosheets on TiO2 Nanoribbons as 2D/1D Heterojunction Photocatalysts with Improved Photocatalytic Performance under Visible Light

Abstract

We report the construction of 2D/1D heterojunction photocatalysts through the hydrothermal growth of WO3 nanosheets on TiO2 nanoribbons for the first time. Two-dimensional WO3 nanosheets were vertically arrayed on the surface of TiO2 nanoribbons, and the growth density could be simply controlled by adjusting the concentration of the precursors. The construction of WO3/TiO2 heterojunctions not only decreases the band gap energy of TiO2 from 3.12 to 2.30 eV and broadens the photoresponse range from the UV region to the visible light region but also significantly reduces electron–hole pair recombination and enhances photo-generated carrier separation. Consequently, WO3/TiO2 heterostructures exhibit improved photocatalytic activity compared to pure WO3 nanosheets and TiO2 nanoribbons upon visible light irradiation. WO3/TiO2-25 possesses the highest photocatalytic activity and can remove 92.8% of RhB pollutants in 120 min. Both further increase and decrease in the growth density of WO3 nanosheets result in an obvious reduction in photocatalytic activity. The kinetic studies confirmed that the photocatalytic degradation of RhB follows the kinetics of the pseudo-first-order model. The present study demonstrates that the prepared WO3/TiO2 2D/1D heterostructures are promising materials for photocatalytic removal of organic pollutants to produce clean water.