P-type β-Ni(OH)2 nanoparticles sensitize CdS nanorod array photoanode to prolong charge carrier lifetime and highly improve bias-free visible-light-driven H2 evaluation

• Published in: Applied catalysis. B, Environmental Environmental, 2020-08, Vol.271, p.118945, Article 118945
• Main Authors: Zhu, Tianyu, Liang, Yujie, Wang, Yunan, Wang, Jun, Wang, Wenzhong, Fu, Junli, Yao, Lizhen, Cheng, Ying, Han, Hongsong
• Format: Article
• Language: English
• Subjects: Arrays; Band structure of solids; Bias; Carrier lifetime; CdS nanorod arrays; Charge transfer; Current carriers; Electrochemistry; Emission analysis; Emission measurements; H2 production; Hydrogen production; Irradiation; Light irradiation; Nanoparticles; Nanorods; Nickel compounds; P-n junctions; Photoanodes; photoelectrode; Photoluminescence; Photons; prolonged charge lifetime; p−n junction; Radiation; Recombination; Spectroscopy; Splitting; Water splitting; β-Ni(OH)2@
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2020.118945

We report a novel β-Ni(OH)2@CdS shell-core nanorod array photoanode, which was fabricated by directly growing β-Ni(OH)2 nanoparticles with p-type conduction characteristics onto the surface CdS nanorod arrays, for highly efficient H2 production under bias-free visible light irradiation. [Display omitted] •β-Ni(OH)2@CdS nanorod arrays were fabricated for efficient PEC H2 production.•Photoproduced electron-hole pairs in the photoanode are efficiently separated.•Charge lifetime within the fabricated photoanode is significantly prolonged.•Efficient charge separation is achieved by type-II band alignment and p-n junction.•β-Ni(OH)2@CdS nanorod array photoanode shows remarkably enhanced H2 evolution. Here, we report a novel β-Ni(OH)2@CdS shell-core nanorod array (NRA) photoanode with prolonged lifetime for highly efficient H2 generation. The fabricated photoanode shows drastically enhanced ability to generate H2 from water splitting under bias-free visible light irradiation. The H2 production rate of β-Ni(OH)2@CdS NRA photoelectrode reaches 762.5 μmol h-1, 8 times as high as that of pure CdS NRA photoelectrode. In addition, the constructed β-Ni(OH)2@CdS shell-core NRA photoanode exhibits an outstanding stability. Mott-Schottky measurements clearly demonstrate that both p-n junction and type-II band alignment are established at β-Ni(OH)2 and CdS interface. This unique band structure is highly favorable for the transfer and separation of charge carriers, significantly suppressing charge recombination, as confirmed by photoluminescence emission study. Moreover, the measurements of electrochemical spectroscopy undoubtedly confirm that the lifetime of charge carriers within this unique band structure is significantly prolonged, leading to drastically enhanced photoelectrochemical water splitting for H2 generation.