C=C π Bond Modified Graphitic Carbon Nitride Films for Enhanced Photoelectrochemical Cell Performance
Research output: Journal Publications and Reviews (RGC: 21, 22, 62) › 21_Publication in refereed journal › peer-review
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Detail(s)
Original language | English |
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Pages (from-to) | 1005-1012 |
Journal / Publication | Chemistry - An Asian Journal |
Volume | 12 |
Issue number | 9 |
Publication status | Published - 4 May 2017 |
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Abstract
Applications of graphitic carbon nitride (g-CN) in photoelectrochemical and optoelectronic devices are still hindered due to the difficulties in synthesis of g-CN films with tunable chemical, physical and catalytic properties. Herein we present a general method to alter the electronic and photoelectrochemical properties of g-CN films by annealing. We found that N atoms can be removed from the g-CN networks after annealing treatment. Assisted by theoretical calculations, we confirm that upon appropriate N removal, the adjacent C atoms will form new C=C π bonds. Detailed calculations demonstrate that the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) are located at the structure unit with C=C π bonds and the electrons are more delocalized. Valence band X-ray photoelectron spectroscopy spectra together with optical absorption spectra unveil that the structure changes result in the alteration of the g-CN energy levels and position of band edges. Our results show that the photocurrent density of the annealed g-CN film is doubled compared with the pristine one, thanks to the better charge separation and transport within the film induced by the new C=C π bonds. An ultrathin TiO2 film (2.2 nm) is further deposited on the g-CN film as stabilizer and the photocurrent density is kept at 0.05 mA cm−2 at 1.23 V versus reversible hydrogen electrode after two-cycle stability assessment. This work enables the applications of g-CN films in many electronic and optoelectronic devices.
Research Area(s)
- annealing, electron delocalization, graphitic carbon nitride films, photoelectrochemical cell, pi bonds
Citation Format(s)
C=C π Bond Modified Graphitic Carbon Nitride Films for Enhanced Photoelectrochemical Cell Performance. / Bian, Juncao; Xi, Lifei; Li, Jianfu et al.
In: Chemistry - An Asian Journal, Vol. 12, No. 9, 04.05.2017, p. 1005-1012.Research output: Journal Publications and Reviews (RGC: 21, 22, 62) › 21_Publication in refereed journal › peer-review