Combining Cocatalyst and Oxygen Vacancy to Synergistically Improve Fe<sub>2</sub>O<sub>3</sub> Photoelectrochemical Water Oxidation Performance

Considering the poor conductivity of Fe<sub>2</sub>O<sub>3</sub> and the weak oxygen evolution reaction associated with it, surface hole accumulation leads to electron hole pair recombination, which inhibits the photoelectrochemical (PEC) performance of the Fe<sub>2<...

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Main Authors: Chen Liu, Jiajuan Li, Wenyao Zhang, Changqing Zhu
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Crystals
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Online Access:https://www.mdpi.com/2073-4352/15/1/85
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author Chen Liu
Jiajuan Li
Wenyao Zhang
Changqing Zhu
author_facet Chen Liu
Jiajuan Li
Wenyao Zhang
Changqing Zhu
author_sort Chen Liu
collection DOAJ
description Considering the poor conductivity of Fe<sub>2</sub>O<sub>3</sub> and the weak oxygen evolution reaction associated with it, surface hole accumulation leads to electron hole pair recombination, which inhibits the photoelectrochemical (PEC) performance of the Fe<sub>2</sub>O<sub>3</sub> photoanode. Therefore, the key to improving the PEC water oxidation performance of the Fe<sub>2</sub>O<sub>3</sub> photoanode is to take measures to improve the conductivity of Fe<sub>2</sub>O<sub>3</sub> and accelerate the reaction kinetics of surface oxidation. In this work, the PEC performances of Fe<sub>2</sub>O<sub>3</sub> photoanodes are synergistically improved by combining loaded an FeOOH cocatalyst and oxygen vacancy doping. Firstly, amorphous FeOOH layers are successfully prepared on Fe<sub>2</sub>O<sub>3</sub> nanostructures through simple photoassisted electrodepositon. Then oxygen vacancies are introduced into FeOOH-Fe<sub>2</sub>O<sub>3</sub> through plasma vacuum treatment, which reduces the content of Fe-O (O<sub>L</sub>) and Fe-OH (-OH), jointly promoting the generation of oxygen vacancies. Oxygen vacancy can increase the concentration of most carriers in Fe<sub>2</sub>O<sub>3</sub> and form photo-induced charge traps, promoting the separation of electron holes and enhancing the conductivity of Fe<sub>2</sub>O<sub>3</sub>. The other parts of -OH act as oxygen evolution catalysts to reduce the reaction obstacle of water oxidation and promote the transfer of holes to the electrode/electrolyte interface. The performance of FeOOH-Fe<sub>2</sub>O<sub>3</sub> after plasma vacuum treatment has been greatly improved, and the photocurrent density is about 1.9 times higher than that of the Fe<sub>2</sub>O<sub>3</sub> photoanode. The improvement in the water oxidation performance of PEC is considered to be the synergistic effect of the cocatalyst and oxygen vacancy. All outstanding PEC response characteristics show that the modification of the cocatalyst and oxygen vacancy doping represent a favorable strategy for synergistically improving Fe<sub>2</sub>O<sub>3</sub> photoanode performance.
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spelling doaj-art-f26165b33c8b41d2923de7c1d17313b42025-01-24T13:28:14ZengMDPI AGCrystals2073-43522025-01-011518510.3390/cryst15010085Combining Cocatalyst and Oxygen Vacancy to Synergistically Improve Fe<sub>2</sub>O<sub>3</sub> Photoelectrochemical Water Oxidation PerformanceChen Liu0Jiajuan Li1Wenyao Zhang2Changqing Zhu3Shandong Key Laboratory of Optical Communication Science and Technology, School of Physics Science and Information Technology, Liaocheng University, Liaocheng 252059, ChinaShandong Key Laboratory of Optical Communication Science and Technology, School of Physics Science and Information Technology, Liaocheng University, Liaocheng 252059, ChinaShandong Key Laboratory of Optical Communication Science and Technology, School of Physics Science and Information Technology, Liaocheng University, Liaocheng 252059, ChinaShandong Key Laboratory of Optical Communication Science and Technology, School of Physics Science and Information Technology, Liaocheng University, Liaocheng 252059, ChinaConsidering the poor conductivity of Fe<sub>2</sub>O<sub>3</sub> and the weak oxygen evolution reaction associated with it, surface hole accumulation leads to electron hole pair recombination, which inhibits the photoelectrochemical (PEC) performance of the Fe<sub>2</sub>O<sub>3</sub> photoanode. Therefore, the key to improving the PEC water oxidation performance of the Fe<sub>2</sub>O<sub>3</sub> photoanode is to take measures to improve the conductivity of Fe<sub>2</sub>O<sub>3</sub> and accelerate the reaction kinetics of surface oxidation. In this work, the PEC performances of Fe<sub>2</sub>O<sub>3</sub> photoanodes are synergistically improved by combining loaded an FeOOH cocatalyst and oxygen vacancy doping. Firstly, amorphous FeOOH layers are successfully prepared on Fe<sub>2</sub>O<sub>3</sub> nanostructures through simple photoassisted electrodepositon. Then oxygen vacancies are introduced into FeOOH-Fe<sub>2</sub>O<sub>3</sub> through plasma vacuum treatment, which reduces the content of Fe-O (O<sub>L</sub>) and Fe-OH (-OH), jointly promoting the generation of oxygen vacancies. Oxygen vacancy can increase the concentration of most carriers in Fe<sub>2</sub>O<sub>3</sub> and form photo-induced charge traps, promoting the separation of electron holes and enhancing the conductivity of Fe<sub>2</sub>O<sub>3</sub>. The other parts of -OH act as oxygen evolution catalysts to reduce the reaction obstacle of water oxidation and promote the transfer of holes to the electrode/electrolyte interface. The performance of FeOOH-Fe<sub>2</sub>O<sub>3</sub> after plasma vacuum treatment has been greatly improved, and the photocurrent density is about 1.9 times higher than that of the Fe<sub>2</sub>O<sub>3</sub> photoanode. The improvement in the water oxidation performance of PEC is considered to be the synergistic effect of the cocatalyst and oxygen vacancy. All outstanding PEC response characteristics show that the modification of the cocatalyst and oxygen vacancy doping represent a favorable strategy for synergistically improving Fe<sub>2</sub>O<sub>3</sub> photoanode performance.https://www.mdpi.com/2073-4352/15/1/85photoelectrochemical water splittingFe<sub>2</sub>O<sub>3</sub>cocatalystoxygen vacancysynergistic effect
spellingShingle Chen Liu
Jiajuan Li
Wenyao Zhang
Changqing Zhu
Combining Cocatalyst and Oxygen Vacancy to Synergistically Improve Fe<sub>2</sub>O<sub>3</sub> Photoelectrochemical Water Oxidation Performance
Crystals
photoelectrochemical water splitting
Fe<sub>2</sub>O<sub>3</sub>
cocatalyst
oxygen vacancy
synergistic effect
title Combining Cocatalyst and Oxygen Vacancy to Synergistically Improve Fe<sub>2</sub>O<sub>3</sub> Photoelectrochemical Water Oxidation Performance
title_full Combining Cocatalyst and Oxygen Vacancy to Synergistically Improve Fe<sub>2</sub>O<sub>3</sub> Photoelectrochemical Water Oxidation Performance
title_fullStr Combining Cocatalyst and Oxygen Vacancy to Synergistically Improve Fe<sub>2</sub>O<sub>3</sub> Photoelectrochemical Water Oxidation Performance
title_full_unstemmed Combining Cocatalyst and Oxygen Vacancy to Synergistically Improve Fe<sub>2</sub>O<sub>3</sub> Photoelectrochemical Water Oxidation Performance
title_short Combining Cocatalyst and Oxygen Vacancy to Synergistically Improve Fe<sub>2</sub>O<sub>3</sub> Photoelectrochemical Water Oxidation Performance
title_sort combining cocatalyst and oxygen vacancy to synergistically improve fe sub 2 sub o sub 3 sub photoelectrochemical water oxidation performance
topic photoelectrochemical water splitting
Fe<sub>2</sub>O<sub>3</sub>
cocatalyst
oxygen vacancy
synergistic effect
url https://www.mdpi.com/2073-4352/15/1/85
work_keys_str_mv AT chenliu combiningcocatalystandoxygenvacancytosynergisticallyimprovefesub2subosub3subphotoelectrochemicalwateroxidationperformance
AT jiajuanli combiningcocatalystandoxygenvacancytosynergisticallyimprovefesub2subosub3subphotoelectrochemicalwateroxidationperformance
AT wenyaozhang combiningcocatalystandoxygenvacancytosynergisticallyimprovefesub2subosub3subphotoelectrochemicalwateroxidationperformance
AT changqingzhu combiningcocatalystandoxygenvacancytosynergisticallyimprovefesub2subosub3subphotoelectrochemicalwateroxidationperformance