Structure and Band Alignment Engineering of CdS/TiO₂/Bi₂WO₆ Trilayer Nanoflake Array for Efficient Photoelectrochemical Water Splitting

Abstract

Designing photoanode materials with desirable architecture and band alignment is essential for boosting photoelectrochemical (PEC) water splitting performance. Herein, a trilayer CdS/TiO 2 /Bi 2 WO 6 guest-host photoanode is designed and fabricated, in which highly-porous Bi 2 WO 6 nanoflake array serves as the host skeleton, while CdS nanoparticles function as superb visible light absorber. An ultrathin TiO 2 interlayer is rationally inserted between Bi 2 WO 6 and CdS, which not only assists the uniform growth of CdS, but also serves as a band-matching semiconductor to promote the charge transport. By optimizing the thickness of TiO 2 layer, the resulting trilayer photoanode exhibits higher PEC performance (2.62/4.91 mA cm À 2 at 1.23 V vs. reversible hydrogen electrode without/with the presence of hole scavenger) under AM 1.5G illumination compared with pristine CdS film. The enhancement of PEC performance is attributed to the enlarged surface area and superior light harvesting ability of the 3D nanoflake nanostructure, and improved charge transport efficiency resulting from the cascaded energy level structure.[a] C.

Gigahertz-Based Visible Light Detection Enabled via CdS-Coated TiO2 Nanotube Layers

“…Instead, CdS-coated TNT layers were integrated to provide a material interface that could significantly increase the sensitivity toward visible light based on their lower band gap (2.4 eV). Furthermore, the conduction band alignment (−0.79 to −0.29 eV) 47 between CdS and TiO 2 allows for efficient charge transfer between the layers, providing generated charges a pathway to diffuse along the TNT layers resulting in a measurable permittivity response. To evaluate the CdS-coated TNT layers integration in microwave sensor, the transient response of the resonant amplitude was recorded and is presented in Figure 11.…”

Hierarchical Bi2WO6/TiO2-nanotube composites derived from natural cellulose for visible-light photocatalytic treatment of pollutants

“…In order to solve the aforementioned problems of TiO 2 and Bi 2 WO 6 materials, researchers have fabricated some Bi 2 WO 6 /TiO 2 composites, which were employed in various photocatalytic applications, such as degradation of organic pollutants [ 25 ], oxidation of methane [ 24 ], and production of hydrogen by water splitting [ 26 ]. According to these reports, Bi 2 WO 6 /TiO 2 composites have better photocatalytic activities than those of pure TiO 2 and Bi 2 WO 6 .…”

General In Situ Photoactivation Route with IPCE over 80% toward CdS Photoanodes for Photoelectrochemical Applications

“…Recent efforts have been mainly focused on the construction of various nanostructures [ 17–19 ] and the fabrication of photoelectrodes with heterojunctions. [ 20–22 ] Nowadays, CdS‐based heterostructures such as CdS/NiOOH, [ 23 ] TiO 2 /SrTiO 3 /CdS, [ 24 ] CdS@SnO 2 , [ 25 ] CdS/TiO 2 /Bi 2 WO 6 , [ 26 ] and CdS‐carbon nanotube‐CoPi [ 27 ] have been fabricated to enhance the PEC water splitting performance. Moreover, other alternative PEC approaches such as using desired selective organic oxidation reactions [ 28 ] rather than water oxidation were proposed as well, which can fully excavate the potential of CdS photoanodes in other suitable operation conditions with improved efficiency and stability.…”