Simultaneous generation of oxygen vacancies on ultrathin BiOBr nanosheets during visible-light-driven CO2 photoreduction evoked superior activity and long-term stability

Xin Ying Kong, Boon Junn Ng, Kok Hong Tan, Xiaofang Chen, Huanting Wang, Abdul Rahman Mohamed, Siang Piao Chai

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Under the tremendous pressure of imminent energy crisis and anthropogenic climate change, photocatalytic conversion of abandoned CO2 into energy-rich hydrocarbon fuels is highly desirable. However, this solar-to-fuel conversion is unavoidably suppressed by the fast recombination of electron-hole pairs and lack of stability of photocatalysts. To overcome this, we have developed ultrathin BiOBr nanosheets (BOB-NS) with primarily exposed {001} facets. The {001} facets of BOB-NS are comprised of high density O atoms, which are linked to the neighbouring Bi atoms via weak Bi–O bonds with long bond length and low bond energy. After visible-light-driven CO2 photoreduction over BOB-NS, we found that the Bi–O bonds were broken and oxygen vacancy (OV) defects formed on the sample surface. The presence of these OVs was proven to be beneficial for photoactivities as photoinduced electrons were effectively trapped at the OV sites and recombination of charge carriers were inhibited. Generally, the free O atoms from dissociation of CO2 would reoxidize the sample surface, thereby deteriorating the performance of photocatalysts. In contrast, we demonstrated in this study that the OV sites on BOB-NS could be simultaneously regenerated and refreshed as the reactions proceeded, leading to a sustainable activity and long-term stability for CO2 photoreduction.

Original languageEnglish
Pages (from-to)20-27
Number of pages8
JournalCatalysis Today
Volume314
DOIs
Publication statusPublished - 15 Sep 2018

Keywords

  • CO reduction
  • Long-term stability
  • Oxygen vacancy defects
  • Photocatalysis
  • Ultrathin BiOBr nanosheets
  • Visible light

Cite this

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title = "Simultaneous generation of oxygen vacancies on ultrathin BiOBr nanosheets during visible-light-driven CO2 photoreduction evoked superior activity and long-term stability",
abstract = "Under the tremendous pressure of imminent energy crisis and anthropogenic climate change, photocatalytic conversion of abandoned CO2 into energy-rich hydrocarbon fuels is highly desirable. However, this solar-to-fuel conversion is unavoidably suppressed by the fast recombination of electron-hole pairs and lack of stability of photocatalysts. To overcome this, we have developed ultrathin BiOBr nanosheets (BOB-NS) with primarily exposed {001} facets. The {001} facets of BOB-NS are comprised of high density O atoms, which are linked to the neighbouring Bi atoms via weak Bi–O bonds with long bond length and low bond energy. After visible-light-driven CO2 photoreduction over BOB-NS, we found that the Bi–O bonds were broken and oxygen vacancy (OV) defects formed on the sample surface. The presence of these OVs was proven to be beneficial for photoactivities as photoinduced electrons were effectively trapped at the OV sites and recombination of charge carriers were inhibited. Generally, the free O atoms from dissociation of CO2 would reoxidize the sample surface, thereby deteriorating the performance of photocatalysts. In contrast, we demonstrated in this study that the OV sites on BOB-NS could be simultaneously regenerated and refreshed as the reactions proceeded, leading to a sustainable activity and long-term stability for CO2 photoreduction.",
keywords = "CO reduction, Long-term stability, Oxygen vacancy defects, Photocatalysis, Ultrathin BiOBr nanosheets, Visible light",
author = "Kong, {Xin Ying} and Ng, {Boon Junn} and Tan, {Kok Hong} and Xiaofang Chen and Huanting Wang and Mohamed, {Abdul Rahman} and Chai, {Siang Piao}",
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Simultaneous generation of oxygen vacancies on ultrathin BiOBr nanosheets during visible-light-driven CO2 photoreduction evoked superior activity and long-term stability. / Kong, Xin Ying; Ng, Boon Junn; Tan, Kok Hong; Chen, Xiaofang; Wang, Huanting; Mohamed, Abdul Rahman; Chai, Siang Piao.

In: Catalysis Today, Vol. 314, 15.09.2018, p. 20-27.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Simultaneous generation of oxygen vacancies on ultrathin BiOBr nanosheets during visible-light-driven CO2 photoreduction evoked superior activity and long-term stability

AU - Kong, Xin Ying

AU - Ng, Boon Junn

AU - Tan, Kok Hong

AU - Chen, Xiaofang

AU - Wang, Huanting

AU - Mohamed, Abdul Rahman

AU - Chai, Siang Piao

PY - 2018/9/15

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N2 - Under the tremendous pressure of imminent energy crisis and anthropogenic climate change, photocatalytic conversion of abandoned CO2 into energy-rich hydrocarbon fuels is highly desirable. However, this solar-to-fuel conversion is unavoidably suppressed by the fast recombination of electron-hole pairs and lack of stability of photocatalysts. To overcome this, we have developed ultrathin BiOBr nanosheets (BOB-NS) with primarily exposed {001} facets. The {001} facets of BOB-NS are comprised of high density O atoms, which are linked to the neighbouring Bi atoms via weak Bi–O bonds with long bond length and low bond energy. After visible-light-driven CO2 photoreduction over BOB-NS, we found that the Bi–O bonds were broken and oxygen vacancy (OV) defects formed on the sample surface. The presence of these OVs was proven to be beneficial for photoactivities as photoinduced electrons were effectively trapped at the OV sites and recombination of charge carriers were inhibited. Generally, the free O atoms from dissociation of CO2 would reoxidize the sample surface, thereby deteriorating the performance of photocatalysts. In contrast, we demonstrated in this study that the OV sites on BOB-NS could be simultaneously regenerated and refreshed as the reactions proceeded, leading to a sustainable activity and long-term stability for CO2 photoreduction.

AB - Under the tremendous pressure of imminent energy crisis and anthropogenic climate change, photocatalytic conversion of abandoned CO2 into energy-rich hydrocarbon fuels is highly desirable. However, this solar-to-fuel conversion is unavoidably suppressed by the fast recombination of electron-hole pairs and lack of stability of photocatalysts. To overcome this, we have developed ultrathin BiOBr nanosheets (BOB-NS) with primarily exposed {001} facets. The {001} facets of BOB-NS are comprised of high density O atoms, which are linked to the neighbouring Bi atoms via weak Bi–O bonds with long bond length and low bond energy. After visible-light-driven CO2 photoreduction over BOB-NS, we found that the Bi–O bonds were broken and oxygen vacancy (OV) defects formed on the sample surface. The presence of these OVs was proven to be beneficial for photoactivities as photoinduced electrons were effectively trapped at the OV sites and recombination of charge carriers were inhibited. Generally, the free O atoms from dissociation of CO2 would reoxidize the sample surface, thereby deteriorating the performance of photocatalysts. In contrast, we demonstrated in this study that the OV sites on BOB-NS could be simultaneously regenerated and refreshed as the reactions proceeded, leading to a sustainable activity and long-term stability for CO2 photoreduction.

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