CdCl2-assisting heat-treatment: Enhanced photoelectrocatalytic hydrogen generation and stability of CdS/ZnO nanoheterojunction arrays. (24th May 2018)

• Record Type: Journal Article
• Authors: Chen, Wenwen; Wu, Weibing; Yang, Weijie; Zhao, Jizuo; Xiao, Mingjing; Kong, Wentao
• Is Part Of: International journal of hydrogen energy. Volume 43:Number 21(2018)
• Page Start: 9969
• Page End: 9977
• Publication Date: 2018-05-24
• Subjects: Hydrogen generation -- Photoelectrocatalysis -- Cadium sulfide -- Heat-treatment -- Nanoheterojunction array; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2018.04.045
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Hydrogen generation efficiency and stability of the photoelectrocatalytic (PEC) water splitting relate closely to the crystallinity and the interface structure of the photoanodes. Here we demonstrated a feasible strategy for improving the cystallinity and interface quality of the ZnO/CdS nanoheterojunction arrays (NHAs) via CdCl2 -assisting post-treatment. CdCl2 treatment was found to promote the recrystallization and densification of the CdS shell layer, the formation of the Znx Cd1-x S intermediate layer between ZnO and CdS, and the creation of an intermediate band (IB) in the forbidden band of CdS due to the high-density ClS states. Meanwhile, the annealing temperature was also lowered from 550 °C to 430 °C with the assistance of CdCl2 treatment. These improvements facilitate the seperation and transport of the photogenerated carriers and extends the light absorption range, resulting in extremely enhanced photocatalytic current and stability. Consequently, the photocatalytic currency reaches to 22 mA cm −2 under the 100 mW cm −2 illumination with the xenon lamp (λ > 420 nm), which is nearly two times larger than that annealed solely at 550 °C but without CdCl2 treatment. The photocatalytic current remains 92% of the initial value after 20-h photocatalytic test. Graphical abstract: Highlights: CdCl2 improves the crystallinity and density of CdS layer and the interface quality. CdCl2 lowered the post-treating temperature greatly and introduced Cls states in CdS. The IB band formed by the Cls states improves the PEC efficiency remarkably. PEC current rises to 22 mA cm −2 and remains 92% of the initial value after 20-h test. This work provides another route for developing excellent CdS/ZnO photocatalysts.