Effects of H₂O₂ generation over visible light-responsive Bi/Bi₂O₂₋ₓCO₃ nanosheets on their photocatalytic NOₓ removal performance

Yanfeng LU, Yu HUANG, Yufei ZHANG, Tingting HUANG, Haiwei LI, Jun-ji CAO, Wing Kei HO

Research output: Contribution to journalArticle

Abstract

The photocatalytic removal of gaseous NOₓ is commonly accompanied by secondary pollution, which necessitates the development of highly efficient nanostructured catalysts with a decreased propensity to toxic intermediate production. Herein, we describe the synthesis of plasmonic Bi/Bi₂O₂₋ₓCO₃ and demonstrate the presence of surface oxygen vacancies therein, revealing that the maximal NOₓ removal efficiency of Bi/Bi₂O₂₋ₓCO₃ under visible light irradiation reached 50.5% and exceeded that of a commercial photocatalyst, while the production of toxic NO₂ as a by-product was completely suppressed (the selectivity reached up to 98%). In-situ introduction of plasmonic Bi on the surface of Bi₂O₂₋ₓCO₃ promoted the generation of H₂O₂ by capturing electrons from the defect states of Bi₂O₂₋ₓCO₃ via the two-electron reduction of O₂ and thus inhibited NO₂ production (as confirmed by scavenger experiments), additionally broadening the light absorption range of the above photocatalyst. Moreover, surface oxygen vacancies in Bi–O layers provided a channel for electron transfer between Bi and Bi₂O₂₋ₓCO₃, which resulted in increased charge separation efficiency (maximum photocurrent = 1.1 μA cm⁻², 14.5 times higher than that of pristine Bi₂O₂CO₃). Furthermore, the toxicity assessment authenticated good biocompatibility of Bi/Bi₂O₂₋ₓCO₃. Thus, this study sheds light on the possible roles of H₂O₂ in NOₓ degradation and provides an efficient surface engineering strategy to prepare highly reactive and selective photocatalysts. Copyright © 2019 Elsevier B.V. All rights reserved.
Original languageEnglish
Pages (from-to)374-382
JournalChemical Engineering Journal
Volume363
Early online dateFeb 2019
DOIs
Publication statusPublished - May 2019

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Nanosheets
Photocatalysts
Poisons
Oxygen vacancies
electron
Electrons
oxygen
scavenger
Photocurrents
Biocompatibility
Light absorption
defect
Byproducts
Toxicity
irradiation
Pollution
catalyst
Irradiation
toxicity
engineering

Bibliographical note

Lu, Y., Huang, Y., Zhang, Y., Huang, T., Li, H., Cao, J.-J., & Ho, W. (2019). Effects of H₂O₂ generation over visible light-responsive Bi/Bi₂O₂₋ₓCO₃ nanosheets on their photocatalytic NOₓ removal performance. Chemical Engineering Journal, 363, 374-382. doi: 10.1016/j.cej.2019.01.172

Keywords

  • Photocatalysis
  • NO oxidation
  • Oxygen vacancy
  • H₂O₂
  • Selectivity