Enhanced photoelectrochemical water-splitting performance of TiO2 nanorods sensitized with CdS via hydrothermal approach

• Published in: Journal of alloys and compounds Vol. 803; pp. 456 - 465
• Main Authors: Diby, N’dri Dieudonné, Duan, Yueqin, Grah, Patrick Atheba, Cai, Fengshi, Yuan, Zhihao
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 30-09-2019; Elsevier BV
• Subjects: CdS sensitization; Current carriers; Electrochemical impedance spectroscopy; Hydrogen production; Hydrothermal reactions; Hydrothermal synthesis; Metal oxide semiconductors; Nanorods; Photoelectric effect; Photoelectric emission; Photoelectrochemical stability; Photoelectrochemical water splitting; Photoelectrons; Quantum efficiency; Raman spectroscopy; Reaction time; Reagents; Separation; Silver chloride; Spectrum analysis; Stability; TiO2 nanorods; Titanium dioxide; Water splitting; X ray photoelectron spectroscopy; TiO2 nanorods; Photoelectrochemical stability; CdS sensitization; Hydrothermal synthesis; Photoelectrochemical water splitting
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2019.05.364

In the photoelectrochemical (PEC) water splitting for the hydrogen production, the fabrication of a stable and efficient photocatalyst semiconductor remains a challenge. CdS, which is one of most used chalcogenide materials, coupled with metal oxide semiconductor exhibit a generally low durability. TiO2 nanorods arrays (TNR) sensitized with CdS were synthesized via hydrothermal method and denoted as TNR-CdS. CdS deposition on TNR surface was controlled by regulating the hydrothermal reaction time. The samples were characterized by X-ray diffraction, Raman spectroscopy, scanning electronmicroscopy, X-ray photoelectron spectroscopy, and UV-visible absorption. A high PEC performance as well as a great CdS sensitized TNR photoanodes stability were exhibited. These results could be due to the intimate contact between CdS and TNR, favoring a fast separation of photogenerated charge carriers. The optimal PEC performance was achieved when CdS was deposited on TNR for 10 h. Under AM 1.5G illumination at applied potential of 0 V vs Ag/AgCl, TNR-CdS (10 h) is found to have a photocurrent density of 6.5 mA/cm2 against 2.25 mA/cm2 for TNR. Additionally, TNR-CdS (10 h) presented a photoconversion efficiency of 2.5% at −0.4 V vs Ag/AgCl, while that of TNR was 0.9% at-0.35 V vs Ag/AgCl. TNR-CdS showed great stability with and without sacrificial reagent. These results were confirmed by electrochemical impedance spectroscopy measurements, where the rapid transfer/transport and separation of photogenerated charge carriers were highlighted.
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•CdS was deposed on TiO2 nanorods (TNR-CdS) using hydrothermal method.•The TNR-CdS showed a photocurrent of 6.5 mA/cm2 against 2.25 mA/cm2 for TNR at 0 V vs Ag/AgCl.•TNR-CdS presented a photoconversion efficiency of 2.5% at −0.4 V vs Ag/AgCl against 0.9% for TNR.•In the absence of sacrificial reagent TNR-CdS showed a long time stability.