scholarly journals Porous g-C3N4 with defects for the efficient Dye photodegradation under visible light

2021 ◽  
Author(s):  
Jing Chen ◽  
Yage Zhang ◽  
Baofan Wu ◽  
Zhichao Ning ◽  
Miaoyan Song ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Methyl Orange ◽  
Visible Light ◽  
Active Sites ◽  
Carbon Nitride ◽  
Narrow Band ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
Electron Hole ◽  
High Durability

Abstract Porous graphitic carbon nitride (p-C3N4) was fabricated via simply pyrolyzing treatment of graphitic carbon nitride (g-C3N4). The defects could be introduced into the structure of g-C3N4 by the broken of some bonds, which was beneficial for the generation of electron-hole pairs and restraining their recombination. Compared with g-C3N4, p-C3N4 showed a narrow band gap to promote the utilization of visible light. Furthermore, the porous structure also increased the specific surface area to maximize the exposure of active sites and promote the mass transfer during photodegradation. As a result, the as-reported p-C3N4 exhibited considerably higher degradation efficiency for Rhodamine B (RhB) and Methyl Orange (MO) than that of pristine g-C3N4. Moreover, the photocatalyst showed high durability and stability in recycling experiments.

scholarly journals Photoelectrochemical Studies on Metal-Doped Graphitic Carbon Nitride Nanostructures under Visible-Light Illumination

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 983 ◽  
Author(s):  
I. Neelakanta Reddy ◽  
N. Jayashree ◽  
V. Manjunath ◽  
Dongseob Kim ◽  
Jaesool Shim
Keyword(s):  
Charge Transfer ◽  
Visible Light ◽  
Light Absorption ◽  
Carbon Nitride ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
Electron Hole ◽  
Photoelectrochemical Activity ◽  
Catalytic Sites ◽  
Metal Doped

Recently, the engineering of optical bandgaps and morphological properties of graphitic carbon nitride (g-C3N4) has attracted significant research attention for photoelectrodes and environmental remediation owing to its low-cost synthesis, availability of raw materials, and thermal physical–chemical stability. However, the photoelectrochemical activity of g-C3N4-based photoelectrodes is considerably poor due to their high electron–hole recombination rate, poor conductivity, low quantum efficiency, and active catalytic sites. Synthesized Ni metal-doped g-C3N4 nanostructures can improve the light absorption property and considerably increase the electron–hole separation and charge transfer kinetics, thereby initiating exceptionally enhanced photoelectrochemical activity under visible-light irradiation. In the present study, Ni dopant material was found to evince a significant effect on the structural, morphological, and optical properties of g-C3N4 nanostructures. The optical bandgap of the synthesized photoelectrodes was varied from 2.53 to 2.18 eV with increasing Ni dopant concentration. The optimized 0.4 mol% Ni-doped g-C3N4 photoelectrode showed a noticeably improved six-fold photocurrent density compared to pure g-C3N4. The significant improvement in photoanode performance is attributable to the synergistic effects of enriched light absorption, enhanced charge transfer kinetics, photoelectrode/aqueous electrolyte interface, and additional active catalytic sites for photoelectrochemical activity.

scholarly journals Photocatalytic Performance of Alkaline Activated Graphitic Carbon Nitride Under Blue LED Light

2021 ◽  
pp. X
Author(s):  
Yong OUYANG ◽  
Jianquan XU ◽  
Aiyu YANG ◽  
Caixia ZHONG ◽  
Wenjing HU ◽  
...  
Keyword(s):  
Visible Light ◽  
Specific Surface ◽  
Active Sites ◽  
Carbon Nitride ◽  
Photocatalytic Performance ◽  
Organic Dyes ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
Simple Method ◽  
Carrier Recombination

Graphitic carbon nitride (g-C3N4) is a metal-free photocatalyst with visible light response. However, the disadvantages limit its application in a wider range, such as its small specific surface areas, fewer active sites, narrow visible light absorption range and high photogenic carrier recombination. In this paper, NaOH was used as activator for alkaline activation of g-C3N4. The phase composition, micromorphology, surface chemical state and optical properties of g-C3N4 after activation were tested. The photocatalytic performance of g-C3N4 over organic dyes was also tested. The results showed that Na+ entered the interlayers of g-C3N4, expanding the spaces between layers. The specific surface area and pore volume of powder were increased. The active sites were increased. The band gap was decreased, and the photogenic carrier recombination was reduced. Alkaline activated g-C3N4 had better adsorption and degradation performance over rhodamine B and methyl orange than inactivated g-C3N4. Therefore, the alkaline activated g-C3N4 promotes its further application in the field of wastewater treatment. This work sheds light on the material modification through a simple method with the aim to efficiently use solar energy.

Highly dispersive and stable Fe3+ active sites on 2D graphitic carbon nitride nanosheets for efficient visible-light photocatalytic nitrogen fixation

2019 ◽  
Vol 7 (48) ◽  
pp. 27547-27559 ◽  
Author(s):  
Chengkai Yao ◽  
Ran Wang ◽  
Zhongsen Wang ◽  
Hua Lei ◽  
Xiaoping Dong ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Visible Light ◽  
Active Sites ◽  
Carbon Nitride ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
Carbon Nitride Nanosheets ◽  
Capture Capacity ◽  
Visible Light Photocatalytic

Highly dispersive and stable chelated Fe active sites on 2D graphitic carbon nitride nanosheets exhibit effective N2 molecule capture capacity for improving visible-light photocatalytic N2 fixation performance.

Co3O4/g-C3N4 Nanocomposites Prepared via Ultrasonication as Active Photocatalyst for H2 Generation Beneath Visible Light

2020 ◽  
Vol 12 (3) ◽  
pp. 285-295
Author(s):  
Maha Alhaddad ◽  
R. M. Navarro ◽  
M. A. Hussein ◽  
R. M. Mohamed
Keyword(s):  
Visible Light ◽  
Carbon Nitride ◽  
Hydrogen Generation ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
Maximum Efficiency ◽  
Glycerol Solution ◽  
Electron Hole ◽  
H2 Generation ◽  
Hole Recombination

In this paper, we introduce an active photocatalyst for hydrogen generation from aqueous glycerol solution on nanoheterojunctions of graphitic carbon nitride (g-C3N4) and Co3O4 at various Co3O4 loading (1∼4 wt.%). The Co3O4 nanoparticulates were efficiently spread on the exterior of exfoliated mesoporous g-C3N4 by means of ultrasonication-mixture method that allowed the formation of effective Co3O4/g-C3N4 heterojunctions that minimized high recombination of charges observed on bare g-C3N4. The formation of nanoheterojunctions amid Co3O4 and g-C3N4 was demonstrated by XPS and HRTEM. Moreover, their number and efficiency in separation of charges depended on Co3O4 loading (maximum efficiency at 3 mol% of Co3O4). The optimal Co3O4/g-C3N4 nanocomposite demonstrated 22.5 and 33.7 times higher H2 production using visible light compared to the parent g-C3N4 and Co3O4 systems, respectively. The differences in photocatalytic action for the Co3O4/g-C3N4 composites was examined in terms of changes in their capacity to engross the light and to diminution the electron-hole recombination associated with different development of nanoheterojunctions in the composites.

scholarly journals Prediction of Band Gap Energy of Doped Graphitic Carbon Nitride Using Genetic Algorithm-Based Support Vector Regression and Extreme Learning Machine

Symmetry ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 411
Author(s):  
Taoreed O. Owolabi ◽  
Mohd Amiruddin Abd Rahman
Keyword(s):  
Genetic Algorithm ◽  
Visible Light ◽  
Band Gap ◽  
Carbon Nitride ◽  
Activation Function ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
Support Vector ◽  
Learning Machine ◽  
Photocatalytic Applications

Graphitic carbon nitride is a stable and distinct two dimensional carbon-based polymeric semiconductor with remarkable potentials in organic pollutants degradation, chemical sensors, the reduction of CO2, water splitting and other photocatalytic applications. Efficient utilization of this material is hampered by the nature of its band gap and the rapid recombination of electron-hole pairs. Heteroatom incorporation due to doping alters the symmetry of the semiconductor and has been among the adopted strategies to tailor the band gap for enhancing the visible-light harvesting capacity of the material. Electron modulation and enhancement of reaction active sites due to doping as evident from the change in specific surface area of doped graphitic carbon nitride is employed in this work for modeling the associated band gap using hybrid genetic algorithm-based support vector regression (GSVR) and extreme learning machine (ELM). The developed GSVR performs better than ELM-SINE (with sine activation function), ELM-TRANBAS (with triangular basis activation function) and ELM-SIG (with sigmoid activation function) model with performance enhancement of 69.92%, 73.59% and 73.67%, respectively, on the basis of root mean square error as a measure of performance. The four developed models are also compared using correlation coefficient and mean absolute error while the developed GSVR demonstrates a high degree of precision and robustness. The excellent generalization and predictive strength of the developed models would ultimately facilitate quick determination of the band gap of doped graphitic carbon nitride and enhance its visible-light harvesting capacity for various photocatalytic applications.

scholarly journals Electrostatic interaction mechanism of visible light absorption broadening in ion-doped graphitic carbon nitride

RSC Advances ◽  
2021 ◽  
Vol 11 (37) ◽  
pp. 22652-22660
Author(s):  
Zengyu Cen ◽  
Yuna Kang ◽  
Rong Lu ◽  
Anchi Yu
Keyword(s):  
Visible Light ◽  
Electrostatic Interaction ◽  
Light Absorption ◽  
Carbon Nitride ◽  
Interaction Mechanism ◽  
Graphitic Carbon ◽  
Electrostatic Attraction ◽  
Graphitic Carbon Nitride ◽  
Visible Light Absorption

H2O2 treated K-doped graphitic carbon nitride presents an enhanced visible light absorption, which is due to the electrostatic attraction between K ions and OOH ions inside graphitic carbon nitride.

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