Synthesis of Nanovoid Bi₂WO₆ 2D Ordered Arrays as Photoanodes for Photoelectrochemical Water Splitting

Abstract

Herein we report a facile and economic method to prepare nanovoid Bi(2)WO(6) 2D ordered arrays employing a simple self-assembly procedure. The electrochemical properties and performance of the 2D nanoarray as a photoanode for water splitting are investigated and compared with a conventional photoanode of similar thickness. The 2D array photoanode shows a much higher photocurrent density and photon-to-H(2) conversion efficiency even with a small content of the Bi(2)WO(6) material. The enhancement is further studied and explained on the basis of the superiority of light scattering and photogenerated hole diffusion within the 2D array structure. This work provides a facile method to improve the efficiency of solar energy conversion systems by minimizing the charge-carrier diffusion length and reducing the light reflection, as well as reducing the amount of the semiconductor material (often costly and/or rare) present in the photoanode.

Structural analysis and optical properties of the Bi2−xYxWO6 system

“…8–11 To a large extent, this interest originates from their relatively narrow bandgaps owing to the mixing of Bi 6s and O 2p orbitals, which leads to a cathodic shift in the position of the valence band. 12 …”

Recent Advances in Bismuth‐Based Nanomaterials for Photoelectrochemical Water Splitting

“…[89] Ac olloidal sphere array is used as at emplate, and this is followed by infiltration of the voids with as ol precursor.T he inverse opal structure is formedb yr emoving the templateb ye tching or calcination. [90] The 2D arrays lower the recombination rate by shortening the diffusion length for the holes, as depicted in Figure 7c-e. First, the precursor for the ternary metal oxide shouldb eh omogenously mixed in the molecular scale to achieve apure phase of the material.…”

“…[91] Bi 2 WO 6 showsH 2 evolution and poor oxygen evolution. [90] i-Bi 2 WO 6 and n-Bi 2 WO 6 correspond to inverse and opal Bi 2 WO 6 in panel b. Reproduced from Refs. Hill and Choi have synthesized Bi 2 WO 6 by thermal treatment of electrodeposited porous WO 3 .…”

“…In this study, the authors considerat wo-electrode system to evaluatet he photocurrent of Bi 2 WO 6 .I tis difficult to measuret he efficiency of the cell and the flatb and potentiala ccurately,a st here is no reference potentiala vailable. [89,90] with permissionf rom Wiley. [92] The development of am ethodt oo btain an ordered morphology with good crystallinity for am ixed metal oxide such as Bi 2 WO 6 remains ac hallenging task.…”

Pt/Bi2WO6 composite microflowers: High visible light photocatalytic performance and easy recycle

“…Zhang et al [29] found that the porous Bi 2 WO 6 films offer a highly enhanced photocatalytic activity under illumination with visible light in comparison to the corresponding nonporous films. Other Bi 2 WO 6 nanocrystals with unusual activity, such as nanosheets [30,31], and nanovoid ordered arrays [32], nanofibrous mats [33] were reported. Nanosized photocatalysts have some superior property in aqueous photocatalytic reactions due to their large surface area, good dispersion, and etc.…”