Details
| Original language | English |
|---|---|
| Pages (from-to) | 10004-10017 |
| Number of pages | 14 |
| Journal | ACS catalysis |
| Volume | 12 |
| Issue number | 16 |
| Early online date | 2 Aug 2022 |
| Publication status | Published - 19 Aug 2022 |
Abstract
Semiconductor-based photocatalysis is an ideal method for air purification by eliminating nitrogen oxide (NO). However, sluggish carrier separation, photocatalysts deactivation and incomplete oxidation are significant bottlenecks for photocatalytic treatment of indoor pollutant NO. Herein, ZnO with assorted structures is fabricated and undergoes further modification for deliberate surface defect constructions. Utilized flux agents during the synthesis provide a more feasible reducing atmosphere, under which spontaneous generations of the surface vacancies become easier, and gradient concentrations are precisely controlled. Photocatalyst characterizations affirm the successful creation of surface defects, which are further evaluated by solar-light-driven NO (ppb level) removal investigations. Results showed that ZnO rich in oxygen vacancies (VO-rich ZnO) exhibited 5.43 and 1.63 times enhanced NO removal with fewer toxic product NO2 formations than its counterparts pristine and VO-poor ZnO, respectively. Importantly, with higher VO on the unusual nonpolar facets, VO-rich ZnO does not only display enhanced NO conversion, but also shows the unselective NO removal process by producing NO3-. The plausible reaction mechanisms of promoted NO conversions are further investigated based on the surface VO, well-positioned band structures, and enhanced carrier separations. Results showed that the surface VO with gradient concentrations are not only promoted carrier separation, but also facilitate molecular oxygen activation, leading to the generations of strong oxidant superoxide radicals (·O2-), and contributing to the enhanced improved efficiency. Adsorption of small molecules (O2, H2O and NO) on the defective surface was further investigated by density functional theory (DFT) calculations, which validated the successful adsorption/activation of NO and O2, further contributed to the improved NO conversions.
Keywords
- carrier separation, NO removal, photocatalysis, surface defects, surface-interface
ASJC Scopus subject areas
- Chemistry(all)
- General Chemistry
- Chemical Engineering(all)
- Catalysis
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In: ACS catalysis, Vol. 12, No. 16, 19.08.2022, p. 10004-10017.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - ZnO with Controllable Oxygen Vacancies for Photocatalytic Nitrogen Oxide Removal
AU - Hailili, Reshalaiti
AU - Ji, Hongwei
AU - Wang, Kaiwen
AU - Dong, Xing’an
AU - Chen, Chuncheng
AU - Sheng, Hua
AU - Bahnemann, Detlef W.
AU - Zhao, Jincai
N1 - Funding Information: Financial support by the National Natural Science Foundation of China (Nos. 21902161 and 22076193), the National Key R&D Program of China (No. 2020YFA0710303) and the Postdoctoral Science Foundation of China (Nos. 2019T120137 and 2018M641484) is gratefully appreciated. R.H. also gratefully acknowledges the support from the Alexander von Humboldt Foundation. We all thank National Supercomputer Center in LvLiang of China for DFT calculations on TianHe-2. Publisher Copyright: © 2022 American Chemical Society. All rights reserved.
PY - 2022/8/19
Y1 - 2022/8/19
N2 - Semiconductor-based photocatalysis is an ideal method for air purification by eliminating nitrogen oxide (NO). However, sluggish carrier separation, photocatalysts deactivation and incomplete oxidation are significant bottlenecks for photocatalytic treatment of indoor pollutant NO. Herein, ZnO with assorted structures is fabricated and undergoes further modification for deliberate surface defect constructions. Utilized flux agents during the synthesis provide a more feasible reducing atmosphere, under which spontaneous generations of the surface vacancies become easier, and gradient concentrations are precisely controlled. Photocatalyst characterizations affirm the successful creation of surface defects, which are further evaluated by solar-light-driven NO (ppb level) removal investigations. Results showed that ZnO rich in oxygen vacancies (VO-rich ZnO) exhibited 5.43 and 1.63 times enhanced NO removal with fewer toxic product NO2 formations than its counterparts pristine and VO-poor ZnO, respectively. Importantly, with higher VO on the unusual nonpolar facets, VO-rich ZnO does not only display enhanced NO conversion, but also shows the unselective NO removal process by producing NO3-. The plausible reaction mechanisms of promoted NO conversions are further investigated based on the surface VO, well-positioned band structures, and enhanced carrier separations. Results showed that the surface VO with gradient concentrations are not only promoted carrier separation, but also facilitate molecular oxygen activation, leading to the generations of strong oxidant superoxide radicals (·O2-), and contributing to the enhanced improved efficiency. Adsorption of small molecules (O2, H2O and NO) on the defective surface was further investigated by density functional theory (DFT) calculations, which validated the successful adsorption/activation of NO and O2, further contributed to the improved NO conversions.
AB - Semiconductor-based photocatalysis is an ideal method for air purification by eliminating nitrogen oxide (NO). However, sluggish carrier separation, photocatalysts deactivation and incomplete oxidation are significant bottlenecks for photocatalytic treatment of indoor pollutant NO. Herein, ZnO with assorted structures is fabricated and undergoes further modification for deliberate surface defect constructions. Utilized flux agents during the synthesis provide a more feasible reducing atmosphere, under which spontaneous generations of the surface vacancies become easier, and gradient concentrations are precisely controlled. Photocatalyst characterizations affirm the successful creation of surface defects, which are further evaluated by solar-light-driven NO (ppb level) removal investigations. Results showed that ZnO rich in oxygen vacancies (VO-rich ZnO) exhibited 5.43 and 1.63 times enhanced NO removal with fewer toxic product NO2 formations than its counterparts pristine and VO-poor ZnO, respectively. Importantly, with higher VO on the unusual nonpolar facets, VO-rich ZnO does not only display enhanced NO conversion, but also shows the unselective NO removal process by producing NO3-. The plausible reaction mechanisms of promoted NO conversions are further investigated based on the surface VO, well-positioned band structures, and enhanced carrier separations. Results showed that the surface VO with gradient concentrations are not only promoted carrier separation, but also facilitate molecular oxygen activation, leading to the generations of strong oxidant superoxide radicals (·O2-), and contributing to the enhanced improved efficiency. Adsorption of small molecules (O2, H2O and NO) on the defective surface was further investigated by density functional theory (DFT) calculations, which validated the successful adsorption/activation of NO and O2, further contributed to the improved NO conversions.
KW - carrier separation
KW - NO removal
KW - photocatalysis
KW - surface defects
KW - surface-interface
UR - http://www.scopus.com/inward/record.url?scp=85135977938&partnerID=8YFLogxK
U2 - 10.1021/acscatal.2c02326
DO - 10.1021/acscatal.2c02326
M3 - Article
VL - 12
SP - 10004
EP - 10017
JO - ACS catalysis
JF - ACS catalysis
SN - 2155-5435
IS - 16
ER -