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

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.