Electron Shuttle in the MOF Derived TiO2/CuO Heterojunction Boosts Light Driven Hydrogen Evolution

Document Type

Article

Publication Date

1-2021

Publisher

Royal Society of Chemistry

Source Publication

Journal of Materials Chemistry

Source ISSN

0959-9428

Abstract

Metal organic frameworks (MOFs) have emerged as a novel template to develop porous photocatalytic materials for solar fuel conversion. In this work, we report the synthesis, charge separation dynamics, and photocatalytic performance of the TiO2/CuO heterostructure derived from mixed-phase MOFs based on Ti and Cu metal nodes, which demonstrates significantly enhanced catalytic activity for the hydrogen evolution reaction (HER) compared to metal oxides derived from single node MOFs. More importantly, using transient absorption spectroscopy, we identified the specific role each component in the heterostructure plays and unravelled the key intermediate species that is responsible for the exceptional photocatalytic activity of the heterostructure. We found that the HER is initiated with ultrafast electron transfer (fs) from the molecular photosensitizer to the conduction band of TiO2, where TiO2 acts as an electron mediator and shuttles the electron to the CuO cocatalyst, facilitating charge separation and ultimately boosting the HER efficiency. These results not only demonstrate the great potential of using mixed-phase MOFs as templates to synthesize mesoporous heterostructure photocatalysts but also provide important insight into the HER mechanism.

Comments

Journal of Materials Chemistry, Vol. 9, No. 10 (January 2021): 6180-6187. DOI.

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