Defect Engineering and Surface Polarization of TiO2 Nanorod Arrays toward Efficient Photoelectrochemical Oxygen Evolution

The relatively low photo-conversion efficiencies of semiconductors greatly restrict their real-world practices toward photoelectrochemical water splitting. In this work, we demonstrate the fabrication of TiO2-x nanorod arrays enriched with oxygen defects and surface-polarized hydroxyl groups by a fa...

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Bibliographic Details
Published inCatalysts Vol. 12; no. 9; p. 1021
Main Authors Li, Yueying, Liang, Shiyu, Sun, Huanhuan, Hua, Wei, Wang, Jian-Gan
Format Journal Article
LanguageEnglish
Published Basel MDPI AG 01.09.2022
Subjects
Arrays
Catalysts
Charge efficiency
Charge transport
Chemical reactions
Contact angle
Current efficiency
defect engineering
Defects
Efficiency
Electric fields
Electrolytes
Engineering
Hydroxyl groups
Nanorods
Oxidation
Oxygen enrichment
Photoelectric effect
photoelectrochemical water splitting
Polarization
Reaction kinetics
Separation
Spectrum analysis
Surface charge
surface polarization
Surface treatment
Titanium dioxide
Water splitting
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Summary:The relatively low photo-conversion efficiencies of semiconductors greatly restrict their real-world practices toward photoelectrochemical water splitting. In this work, we demonstrate the fabrication of TiO2-x nanorod arrays enriched with oxygen defects and surface-polarized hydroxyl groups by a facile surface reduction method. The oxygen defects located in the bulk/surface of TiO2-x enable fast charge transport and act as catalytically active sites to accelerate the water oxidation kinetics. Meanwhile, the hydroxyl groups could establish a surface electric field by polarization, for efficient charge separation. The as-optimized TiO2-x nanorod photoanode achieves a high photocurrent density of 2.62 mA cm−2 without any cocatalyst loading at 1.23 VRHE under 100 mW cm−2, which is almost double that of the bare TiO2 counterpart. Notably, the surface charge separation and injection efficiency of the TiO2-x photoanode reach as high as 80% and 97% at 1.23 VRHE, respectively, and the maximum incident photon-to-current efficiency reaches 90% at 400 nm. This work provides a new surface treatment strategy for the development of high-performance photoanodes in photoelectrochemical water splitting.
ISSN:2073-4344
2073-4344
DOI:10.3390/catal12091021