PbS Quantum Dots-Decorated BiVO 4 Photoanodes for Highly Efficient Photoelectrochemical Hydrogen Production

• Published in: Nanomaterials (Basel, Switzerland) Switzerland), 2023-02, Vol.13 (5)
• Main Authors: Seo, Joo-Won, Ha, Seung-Beom, Song, In-Cheul, Kim, Jae-Yup
• Format: Article
• Language: English
• ISSN: 2079-4991; 2079-4991

While metal oxides such as TiO , Fe O , WO , and BiVO have been previously studied for their potential as photoanodes in photoelectrochemical (PEC) hydrogen production, their relatively wide band-gap limits their photocurrent, making them unsuitable for the efficient utilization of incident visible light. To overcome this limitation, we propose a new approach for highly efficient PEC hydrogen production based on a novel photoanode composed of BiVO /PbS quantum dots (QDs). Crystallized monoclinic BiVO films were prepared via a typical electrodeposition process, followed by the deposition of PbS QDs using a successive ionic layer adsorption and reaction (SILAR) method to form a p-n heterojunction. This is the first time that narrow band-gap QDs were applied to sensitize a BiVO photoelectrode. The PbS QDs were uniformly coated on the surface of nanoporous BiVO , and their optical band-gap was reduced by increasing the number of SILAR cycles. However, this did not affect the crystal structure and optical properties of the BiVO . By decorating the surface of BiVO with PbS QDs, the photocurrent was increased from 2.92 to 4.88 mA/cm (at 1.23 V ) for PEC hydrogen production, resulting from the enhanced light-harvesting capability arising from the narrow band-gap of the PbS QDs. Moreover, the introduction of a ZnS overlayer on the BiVO /PbS QDs further improved the photocurrent to 5.19 mA/cm , attributed to the reduction in interfacial charge recombination.