Defects Promote Ultrafast Charge Separation in Graphitic Carbon Nitride for Enhanced Visible-Light-Driven CO 2 Reduction Activity

Hainan Shi, Saran Long, Jungang Hou, Lu Ye, Yanwei Sun, Wenjun Ni, Chunshan Song, Keyan Li, Gagik G. Gurzadyan, Xinwen Guo

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Fundamental photocatalytic limitations of solar CO 2 reduction remain due to low efficiency, serious charge recombination, and short lifetime of catalysts. Herein, two-dimensional graphitic carbon nitride nanosheets with nitrogen vacancies (g-C 3 N x ) located at both three-coordinate N atoms and uncondensed terminal NH x species were prepared by one-step tartaric acid-assistant thermal polymerization of dicyandiamide. Transient absorption spectra revealed that the defects in g-C 3 N 4 act as trapped states of charges to result in prolonged lifetimes of photoexcited charge carriers. Time-resolved photoluminescence spectroscopy revealed that the faster decay of charges is due to the decreased interlayer stacking distance in g-C 3 N x in favor of hopping transition and mobility of charge carriers to the surface of the material. Owing to the synergic virtues of strong visible-light absorption, large surface area, and efficient charge separation, the g-C 3 N x nanosheets with negligible loss after 15 h of photocatalysis exhibited a CO evolution rate of 56.9 μmol g −1 h −1 under visible-light irradiation, which is roughly eight times higher than that of pristine g-C 3 N 4 . This work presents the role of defects in modulating light absorption and charge separation, which opens an avenue to robust solar-energy conversion performance.

Original languageEnglish (US)
Pages (from-to)5028-5035
Number of pages8
JournalChemistry - A European Journal
Volume25
Issue number19
DOIs
StatePublished - Apr 1 2019

Fingerprint

Carbon nitride
Nanosheets
Carbon Monoxide
Charge carriers
Light absorption
Defects
Photoluminescence spectroscopy
Photocatalysis
Energy conversion
Solar energy
Vacancies
Absorption spectra
Nitrogen
Polymerization
Irradiation
Atoms
Catalysts
Acids
cyanogen
Hot Temperature

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Organic Chemistry

Cite this

Shi, Hainan ; Long, Saran ; Hou, Jungang ; Ye, Lu ; Sun, Yanwei ; Ni, Wenjun ; Song, Chunshan ; Li, Keyan ; Gurzadyan, Gagik G. ; Guo, Xinwen. / Defects Promote Ultrafast Charge Separation in Graphitic Carbon Nitride for Enhanced Visible-Light-Driven CO 2 Reduction Activity In: Chemistry - A European Journal. 2019 ; Vol. 25, No. 19. pp. 5028-5035.
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Defects Promote Ultrafast Charge Separation in Graphitic Carbon Nitride for Enhanced Visible-Light-Driven CO 2 Reduction Activity . / Shi, Hainan; Long, Saran; Hou, Jungang; Ye, Lu; Sun, Yanwei; Ni, Wenjun; Song, Chunshan; Li, Keyan; Gurzadyan, Gagik G.; Guo, Xinwen.

In: Chemistry - A European Journal, Vol. 25, No. 19, 01.04.2019, p. 5028-5035.

Research output: Contribution to journalArticle

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AU - Shi, Hainan

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