Enhanced photocatalytic performance of tungsten oxide through tuning exposed facets and introducing oxygen vacancies

Abstract

It is known that the exposed facet and defect state are crucial to the photocatalytic performance. Here, we report that the exposed facets of the building blocks in the tungsten oxide hierarchical nanostructures could be controlled by adjusting the amount of formamide in the hydrothermal precursor solution and the oxygen vacancies were successfully introduced through the post-air annealing. It is found that exposing high percentage (020) facet is unbeneficial for the photocatalytic performance and (200) and (002) facets should be the photocatalytic active facets of the hexagonal tungsten oxide. The hexagonal tungsten oxide with oxygen vacancies and maximum (200) and (002) facets archives highest photocatalytic performance in degrading rhodamine B under simulated solar light irradiation, which the rate constant per specific surface area (k/SBET) is 7.3 times as high as the sample without oxygen vacancies and minimum (200) and (002) facets. Both introducing oxygen vacancies and exposing (200) and (002) facets can enhance the separation efficiency of photo-generated charges, thus improving the photocatalytic performance.

High-temperature solid-state reaction induced structure modifications and associated photoactivity and gas-sensing performance of binary oxide one-dimensional composite system

“…39 In WO 3 and BiPO 4 oxide semiconductors, research results demonstrate that the surface oxygen vacancy of the oxides accelerates the separation of the photoinduced electronhole pairs and improves the photocatalytic properties accordingly. 40,41 Moreover, the ZnO-ZTO nanorods' having a more rugged surface compared with that of the ZnO-SnO 2 nanorods increased multiple light scattering between the nanorods and irradiated solar light in the photodegradation tests.…”

Effect of the Morphology of Tungsten Oxide Embedded in Sodium Alginate/Polyvinylpyrrolidone Composite Beads on the Photocatalytic Degradation of Methylene Blue Dye Solution

“…Though both forms of WO 3 have terminal oxygen, the highest photocatalytic activity of WO 3 •0.33H 2 O nanorod may be due to higher oxygen vacancies. Y. Li et al reported that the more oxygen vacancies WO 3 crystal has, the higher the photocatalytic activity will be [42]. will dominate on the removal process, and it should be optimized to achieve better removal from the system and allow being reused several times without losing catalytic activity in the photocatalytic dye removal.…”

Tungsten Oxide Nanoplates: Facile Synthesis, Controllable Oxygen Deficiency and Photocatalytic Activity

“…These cutting-edge applications mainly rely on the high charge transferability of WO 3 [6]. The charge transferability of tungsten oxide originates from the crystal structure and the oxygen vacancy on WO 3 [6][7][8][9][10]. The crystal structure of tungsten oxide is counted as the assembly of the WO 6 octahedra via corner-sharing (monoclinic, hexagonal, cubic, orthorhombic, hexagonal, triclinic, tetragonal phases -WO 3 ) and/or edge-sharing (magneli phase -WO 3−x which only appears in the oxygen-deficient environment) arrangements [1,2,11].…”

“…The arrangement of WO 6 octahedra creates tunnels through that small ion could intercalate resulting in ion transferability. The electron transferability of WO 3 originates from the oxygen vacancy on the surface which could be created via crystal transformation during annealing [11,12] or hydrogen treatment [13,14] or engineering the exposed facets [9]. .…”