Defects remodeling of g-C3N4 nanosheets by fluorine-containing solvothermal treatment to enhance their photocatalytic activities

Lin, Wei; Lu, Kangchao; Zhou, Shijian; Wang, Jian; Mu, Feihu; Wang, Yun; Wu, Yong; Kong, Yan

doi:10.1016/j.apsusc.2018.03.140

Cited by 46 publications

(16 citation statements)

References 38 publications

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“…Bragg's law showed no significant change in the d-spacing values among the four samples, implying the robust solvothermal stability of the g-C 3 N 4 photocatalysts (even those prepared with the ethanol solvent) (Table 1) [25,27,28]. As is shown in Figure 4a, the interlayer stacking (002) peak intensity of Pt/CN-160 is lower than that of the other samples, likely indicating that there would be a loss in the stacking ordered structure of the g-C 3 N 4 nanosheet, resulting in a little-layered structure of g-C 3 N 4 [7,[29][30][31][32]. However, when the solvothermal temperature is above 180 • C, the (002) peaks become stronger; this is likely associated with the enhanced crystallinity since defects can be recovered by re-polymerization during the solvothermal process [32].…”

Section: Structural and Chemical Propertiesmentioning

confidence: 99%

“…The absorption spectra of all the as-synthesized samples reach the maximum peaks in the ultraviolet range (wavelengths around 325 nm) with shoulders extending to the visible light region, indicating that all the samples are able to harvest photons from visible light utilizing the O-containing functional groups. When elevating the solvothermal temperature, the absorbance value underwent slight blueshifts, likely because of the well-known quantum confinement effect and the introduction of O-containing functional groups [12,20,32]. Furthermore, Pt/CN-160 and Pt/CN-180 samples reflect higher absorbance intensities compared with those of Pt/CN-140 and Pt/CN-220, indicating that the formers exhibit the stronger absorption ability to harvest more photons under the same irradiation condition.…”

Section: Optical and Photoelectrochemical Propertiesmentioning

confidence: 99%

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Ethanol Solvothermal Treatment on Graphitic Carbon Nitride Materials for Enhancing Photocatalytic Hydrogen Evolution Performance

Nguyen

Dao

et al. 2022

Nanomaterials

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Recently, Pt-loaded graphic carbon nitride (g-C3N4) materials have attracted great attention as a photocatalyst for hydrogen evolution from water. The simple surface modification of g-C3N4 by hydrothermal methods improves photocatalytic performance. In this study, ethanol is used as a solvothermal solvent to modify the surface properties of g-C3N4 for the first time. The g-C3N4 is thermally treated in ethanol at different temperatures (T = 140 °C, 160 °C, 180 °C, and 220 °C), and the Pt co-catalyst is subsequently deposited on the g-C3N4 via a photodeposition method. Elemental analysis and XPS O 1s data confirm that the ethanol solvothermal treatment increased the contents of the oxygen-containing functional groups on the g-C3N4 and were proportional to the treatment temperatures. However, the XPS Pt 4f data show that the Pt2+/Pt0 value for the Pt/g-C3N4 treated at ethanol solvothermal temperature of 160 °C (Pt/CN-160) is the highest at 7.03, implying the highest hydrogen production rate of Pt/CN-160 is at 492.3 μmol g−1 h−1 because the PtO phase is favorable for the water adsorption and hydrogen desorption in the hydrogen evolution process. In addition, the electrochemical impedance spectroscopy data and the photoluminescence spectra emission peak intensify reflect that the Pt/CN-160 had a more efficient charge separation process that also enhanced the photocatalytic activity.

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Section: Structural and Chemical Propertiesmentioning

confidence: 99%

Section: Optical and Photoelectrochemical Propertiesmentioning

confidence: 99%

Ethanol Solvothermal Treatment on Graphitic Carbon Nitride Materials for Enhancing Photocatalytic Hydrogen Evolution Performance

Nguyen

Dao

et al. 2022

Nanomaterials

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“…Nowadays, F-doped, nanostructured carbons have attracted tremendous interest and obtained great success, having controllable mechanical, electronic and magnetic properties [ 18 , 19 , 20 ]. F-doped g-C 3 N 4 can be synthesized by either heating a mixture of dicyandiamide as the precursor with inorganic fluorides at high temperature [ 21 , 22 , 23 ] or via post-fluorination of g-C 3 N 4 with the F-containing solution hydrothermally [ 24 , 25 , 26 , 27 , 28 , 29 ]. Both experimental and theoretical investigations have revealed that the structural distortion induced by F-doping enhances the photocatalytic activity of g-C 3 N 4 because of the narrowed bandgap and accelerated separation of photogenerated electron–hole pairs.…”

Section: Introductionmentioning

confidence: 99%

Gas-Phase Fluorination of g-C3N4 for Enhanced Photocatalytic Hydrogen Evolution

2021

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Graphitic carbon nitride (g-C3N4) has attracted much attention because of its potential for application in solar energy conservation. However, the photocatalytic activity of g-C3N4 is limited by the rapidly photogenerated carrier recombination and insufficient solar adsorption. Herein, fluorinated g-C3N4 (F-g-CN) nanosheets are synthesized through the reaction with F2/N2 mixed gas directly. The structural characterizations and theoretical calculations reveal that fluorination introduces N vacancy defects, structural distortion and covalent C-F bonds in the interstitial space simultaneously, which lead to mesopore formation, vacancy generation and electronic structure modification. Therefore, the photocatalytic activity of F-g-CN for H2 evolution under visible irradiation is 11.6 times higher than that of pristine g-C3N4 because of the enlarged specific area, enhanced light harvesting and accelerated photogenerated charge separation after fluorination. These results show that direct treatment with F2 gas is a feasible and promising strategy for modulating the texture and configuration of g-C3N4-based semiconductors to drastically enhance the photocatalytic H2 evolution process.

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“…However, affected by the boiling point of the solvent, the reaction temperature of the solvothermal method is usually about 200 °C. [ 11–13 ] Under this condition, the ordering and crystallinity of some compounds are poor, and there are many surface defects, which will become the recombination center and accelerate the recombination of electron–hole pairs. The direct annealing methods can achieve a relatively high reaction temperature, but due to factors such as slow diffusion of reactants and small contact area, the performance of the synthesized photocatalyst is also limited.…”

Section: Introductionmentioning

confidence: 99%

Molten‐Salt Technology Application for the Synthesis of Photocatalytic Materials

Luo

Wang

et al. 2021

Energy Tech

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Most of the photocatalytic materials are prepared by wet chemical methods and calcination methods. These preparation methods usually have the problems of slow reaction speed and low crystallinity of products, which seriously restrict the development of photocatalytic technology. Molten salt method (MSM) has attracted much attention of researchers because of its unique advantages in optimizing the synthesis route of photocatalyst. Herein, the application of molten salt technology in the preparation of photocatalytic materials in recent years is summarized. The advantages of MSM in photocatalytic synthesis, such as promoting crystallization, adjusting morphology, accelerating the construction of heterostructure, stabilizing single atom, doping auxiliary elements and adjusting defect position, are also discussed in detail. It is indicated that MSM has important application potential in the preparation of photocatalytic materials. Meanwhile, the research achievements and existing problems of MSM are summarized, and suggestions for further application of MSM in photocatalyst's preparation are put forward.

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Defects remodeling of g-C3N4 nanosheets by fluorine-containing solvothermal treatment to enhance their photocatalytic activities

Cited by 46 publications

References 38 publications

Ethanol Solvothermal Treatment on Graphitic Carbon Nitride Materials for Enhancing Photocatalytic Hydrogen Evolution Performance

Ethanol Solvothermal Treatment on Graphitic Carbon Nitride Materials for Enhancing Photocatalytic Hydrogen Evolution Performance

Gas-Phase Fluorination of g-C3N4 for Enhanced Photocatalytic Hydrogen Evolution

Molten‐Salt Technology Application for the Synthesis of Photocatalytic Materials

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