F- Serve as Surface Trapping Sites to Promote the Charge Separation and Transfer of TiO2

ACS Omega. 2021 Dec 16;6(51):35799-35809. doi: 10.1021/acsomega.1c05891. eCollection 2021 Dec 28.

ABSTRACT

Finding an effective strategy to promote the charge transfer and separation of TiO2 is urgently needed. Herein, a surface fluorination (F-)-modified TiO2 (denoted as TO-xF, where x represents the volume of HF added in the solution) catalyst has been prepared by a mild and facile post-treatment method. The changes induced by surface F- on the morphological, structural, and surface electronic features and the charge separation and transfer efficiency of TiO2 were specifically examined. Compared with pristine TO, TO-0.4F exhibits enhanced photocatalytic degradation of methyl orange and phenol, production of hydroxyl radicals, and photocurrent response. The enhanced photocatalytic activities of TO-0.4F can be attributed to the role of surface F- as surface trapping sites in effectively boosting the charge transfer and separation processes, which is verified by the steady-state and time-resolved fluorescence spectroscopy, electrochemical impedance spectroscopy, Bode plot, transient photocurrent response, and open-circuit voltage measurements. This study emphasizes the role of surface F- in promoting the charge transfer and separation and improving the photocatalytic activity of TiO2.

PMID:34984309 | PMC:PMC8717585 | DOI:10.1021/acsomega.1c05891

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