scholarly journals Conjugated Electron Donor–Acceptor Hybrid Polymeric Carbon Nitride as a Photocatalyst for CO2 Reduction

Molecules ◽  
2019 ◽  
Vol 24 (9) ◽  
pp. 1779 ◽  
Author(s):  
Asif Hayat ◽  
Mati Ur Rahman ◽  
Iltaf Khan ◽  
Javid Khan ◽  
Muhammad Sohail ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Molecular Orbital ◽  
Density Functional ◽  
Carbon Nitride ◽  
Co2 Reduction ◽  
Characterization Methods ◽  
Base Functions ◽  
Activity Performance ◽  
Donor Acceptor ◽  
Polymeric Carbon

This work incorporates a variety of conjugated donor-acceptor (DA) co-monomers such as 2,6-diaminopurine (DP) into the structure of a polymeric carbon nitride (PCN) backbone using a unique nanostructure co-polymerization strategy and examines its photocatalytic activity performance in the field of photocatalytic CO2 reduction to CO and H2 under visible light irradiation. The as-synthesized samples were successfully analyzed using different characterization methods to explain their electronic and optical properties, crystal phase, microstructure, and their morphology that influenced the performance due to the interactions between the PCN and the DPco-monomer. Based on the density functional theory (DFT) calculation result, pure PCN and CNU-DP15.0 trimers (interpreted as incorporation of the co-monomer at two different positions) were extensively evaluated and exhibited remarkable structural optimization without the inclusion of any symmetry constraints (the non-modified sample derived from urea, named as CNU), and their optical and electronic properties were also manipulated to control occupation of their respective highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO). Also, co-polymerization of the donor–acceptor 2,6-diamino-purine co-monomer with PCN influenced the chemical affinities, polarities, and acid–base functions of the PCN, remarkably enhancing the photocatalytic activity for the production of CO and H2 from CO2 by 15.02-fold compared than that of the parental CNU, while also improving the selectivity.

scholarly journals Post-Synthetic Derivatization of Graphitic Carbon Nitride with Methanesulfonyl Chloride: Synthesis, Characterization and Photocatalysis

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 193 ◽  
Author(s):  
Petr Praus ◽  
Aneta Smýkalová ◽  
Kryštof Foniok ◽  
Petr Velíšek ◽  
Daniel Cvejn ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Carbon Nitride ◽  
High Resolution Mass Spectrometry ◽  
Chloride Ions ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
Characterization Methods ◽  
Uva Irradiation ◽  
Amine Groups ◽  
Opposite Manner

Bulk graphitic carbon nitride (CN) was synthetized by heating of melamine at 550 °C, and the exfoliated CN (ExCN) was prepared by heating of CN at 500 °C. Sulfur-doped CN was synthesized by heating of thiourea (S-CN) and by a novel procedure based on the post-synthetic derivatization of CN with methanesulfonyl (CH3SO2−) chloride (Mes-CN and Mes-ExCN). The obtained nanomaterials were investigated by common characterization methods and their photocatalytic activity was tested by means of the decomposition of acetic orange 7 (AO7) under ultraviolet A (UVA) irradiation. The content of sulfur in the modified CN decreased in the sequence of Mes-ExCN > Mes-CN > S-CN. The absorption of light decreased in the opposite manner, but no influence on the band gap energies was observed. The methanesulfonyl (mesyl) groups connected to primary and secondary amine groups were confirmed by high resolution mass spectrometry (HRMS). The photocatalytic activity decreased in the sequence of Mes-ExCN > ExCN > CN ≈ Mes-CN > S-CN. The highest activity of Mes-ExCN and ExCN was explained by the highest amounts of adsorbed Acetic Orange 7 (AO7). In addition, in the case of Mes-ExCN, chloride ions incorporated in the CN lattice enhanced the photocatalytic activity as well.

Doping-induced enhancement of crystallinity in polymeric carbon nitride nanosheets to improve their visible-light photocatalytic activity

Nanoscale ◽  
2019 ◽  
Vol 11 (14) ◽  
pp. 6876-6885 ◽  
Author(s):  
Yuan-Yuan Li ◽  
Bing-Xin Zhou ◽  
Hua-Wei Zhang ◽  
Shao-Fang Ma ◽  
Wei-Qing Huang ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Carbon Nitride ◽  
Structural Defects ◽  
Two Dimensional ◽  
Utilization Ratio ◽  
Carbon Nitride Nanosheets ◽  
Polymeric Carbon ◽  
Visible Light Photocatalytic

Structural defects can greatly inhibit electron transfer in two-dimensional (2D) layered polymeric carbon nitride (CN), seriously lowering its utilization ratio of photogenerated charges during photocatalysis.

scholarly journals Tailoring the Grain Boundary Chemistry of Polymeric Carbon Nitride for Enhanced Solar Hydrogen Production and CO2 Reduction

2019 ◽  
Vol 131 (11) ◽  
pp. 3471-3475 ◽  
Author(s):  
Guigang Zhang ◽  
Guosheng Li ◽  
Tobias Heil ◽  
Spiros Zafeiratos ◽  
Feili Lai ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Grain Boundary ◽  
Carbon Nitride ◽  
Co2 Reduction ◽  
Solar Hydrogen ◽  
Solar Hydrogen Production ◽  
Boundary Chemistry ◽  
Polymeric Carbon

Theoretical investigation on the photocatalytic activity of the Au/g-C3N4 monolayer

2017 ◽  
Vol 16 (02) ◽  
pp. 1750013 ◽  
Author(s):  
Guoyan Nie ◽  
Peng Li ◽  
Jin-Xia Liang ◽  
Chun Zhu
Keyword(s):  
Optical Properties ◽  
Photocatalytic Activity ◽  
Density Functional ◽  
High Stability ◽  
Carbon Nitride ◽  
Visible Region ◽  
Single Layer ◽  
Single Atom ◽  
Two Dimensional ◽  
Hybrid Functional

Two-dimensional optical catalysis materials have a wonderful potential application. Here, a new two-dimensional material consisting of the supported single-atom Au on a graphite carbon nitride (g-C3N[Formula: see text] single layer has been designed and its electronic and optical properties have been characterized by density functional calculations. The bandgap of 1.82[Formula: see text]eV calculated by the hybrid functional HSE06 shows that the Au/g-C3N4 is an indirect semiconductor, and the electron can easily be excited from the single-atom Au to the bottom of the conduction band. This material therefore has relatively strong optical properties in the visible region. Moreover, the process of Au insertion into the cavity of g-C3N4 single layer is energy-favorable. This work may provide insights and a new avenue for fabricating supported Au catalysts with high stability.

scholarly journals Electron rectification through donor-acceptor-heterocyclics connected to cumulenic bridge: a computational study

2007 ◽  
Vol 5 (3) ◽  
pp. 793-812 ◽  
Author(s):  
J. Laxmikanth Rao
Keyword(s):  
Molecular Electronics ◽  
Molecular Orbital ◽  
Density Functional ◽  
Computational Study ◽  
Potential Drop ◽  
Molecular Wires ◽  
Frontier Molecular Orbital ◽  
Double Bonds ◽  
Acceptor Side ◽  
Donor Acceptor

AbstractDensity Functional Theory (DFT) calculations and Frontier Molecular Orbital (FMO) analysis have been carried out at B3LYP/6-31G(d,p) level of theory on some Donor-Bridge-Acceptor (D-B-A) molecules for their electrical rectification behavior. The donor-acceptor-heterocyclics (D/A-heterocyclics) (namely thiophene, furan and pyrrole rings) are attached as donor and acceptors to the two ends of cumulenic bridge. FMO analysis indicates that the molecules having even number of double bonds in the bridge, possess a complete localization of the MOs i.e., the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) are localized on the donor and the acceptor side of the molecules respectively, and LUMO+1 is localized on the donor side, where as in case of odd number of double bonds in the bridge, both the HOMO and LUMOs are delocalized all over the molecule. The Potential Drop (PD) in the former case decreases as the number of double bonds increases in the bridge and due to the presence of the mutually orthogonal and noninteracting π-clouds, they can act as molecular rectifiers. For the molecules with the odd number of double bonds due to the low-lying LUMO delocalized all over the molecule, may find application as molecular wires in molecular electronics circuits.

scholarly journals NIR-Responsive Carbon Nitride of Five-Membered Rings (C3N2) for Photoelectrochemical Biosensing

2020 ◽  
Author(s):  
Hong Yang ◽  
Qing Zhou ◽  
Zhengzou Fang ◽  
Lufang Zhao ◽  
Jin Ma ◽  
...  
Keyword(s):  
Density Functional ◽  
Carbon Nitride ◽  
Density Functional Theory Calculations ◽  
Electronic Band ◽  
Functional Theory ◽  
Hard Materials ◽  
Polymeric Carbon ◽  
First Time ◽  
Electronic Transition Energy

Polymeric carbon nitrides (pCN) have garnered immense attention, ranging from super-hard materials to artificial photosynthesis, due to their exceptional chemical and optoelectronic properties. The most studied C<sub>3</sub>N<sub>4</sub> along with other stoichiometric pCN, such as C<sub>3</sub>N, C<sub>2</sub>N and C<sub>3</sub>N<sub>5</sub>, commonly employed a six-membered ring as the basic units; while the five-membered rings are also popular in a myriad of natural and artificial molecules with a more polarized framework and intriguing functionalities. Here, we report a facile synthesis of C<sub>3</sub>N<sub>2</sub> with a topological structure of five-membered rings, endowing by far the narrowest the first electronic transition energy (0.81 eV) in pCN family. The basic imidazole unit with dangling bonds, resulting in an unusual electronic band of p-π conjugation and split molecular orbitals, was revealed in C<sub>3</sub>N<sub>2</sub> by both experiments and density functional theory calculations. Moreover, a NIR-responsive photoelectrochemical (PEC) biosensor for non-transparent biosamples was constructed for the first time using C<sub>3</sub>N<sub>2</sub> with outstanding performance. This work would not only open a new vista of pCN with different topological structures but also broaden the horizon of their application, such as prospective <i>in vivo</i> PEC bioassay.

scholarly journals NIR-Responsive Carbon Nitride of Five-Membered Rings (C3N2) for Photoelectrochemical Biosensing

2020 ◽  
Author(s):  
Hong Yang ◽  
Qing Zhou ◽  
Zhengzou Fang ◽  
Lufang Zhao ◽  
Jin Ma ◽  
...  
Keyword(s):  
Density Functional ◽  
Carbon Nitride ◽  
Density Functional Theory Calculations ◽  
Electronic Band ◽  
Functional Theory ◽  
Hard Materials ◽  
Polymeric Carbon ◽  
First Time ◽  
Electronic Transition Energy

Polymeric carbon nitrides (pCN) have garnered immense attention, ranging from super-hard materials to artificial photosynthesis, due to their exceptional chemical and optoelectronic properties. The most studied C<sub>3</sub>N<sub>4</sub> along with other stoichiometric pCN, such as C<sub>3</sub>N, C<sub>2</sub>N and C<sub>3</sub>N<sub>5</sub>, commonly employed a six-membered ring as the basic units; while the five-membered rings are also popular in a myriad of natural and artificial molecules with a more polarized framework and intriguing functionalities. Here, we report a facile synthesis of C<sub>3</sub>N<sub>2</sub> with a topological structure of five-membered rings, endowing by far the narrowest the first electronic transition energy (0.81 eV) in pCN family. The basic imidazole unit with dangling bonds, resulting in an unusual electronic band of p-π conjugation and split molecular orbitals, was revealed in C<sub>3</sub>N<sub>2</sub> by both experiments and density functional theory calculations. Moreover, a NIR-responsive photoelectrochemical (PEC) biosensor for non-transparent biosamples was constructed for the first time using C<sub>3</sub>N<sub>2</sub> with outstanding performance. This work would not only open a new vista of pCN with different topological structures but also broaden the horizon of their application, such as prospective <i>in vivo</i> PEC bioassay.

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