scholarly journals Melem (2,5,8-Triamino-tri-s-triazine), an Important Intermediate during Condensation of Melamine Rings to Graphitic Carbon Nitride:  Synthesis, Structure Determination by X-ray Powder Diffractometry, Solid-State NMR, and Theoretical Studies

2003 ◽  
Vol 125 (34) ◽  
pp. 10288-10300 ◽  
Author(s):  
Barbara Jürgens ◽  
Elisabeth Irran ◽  
Jürgen Senker ◽  
Peter Kroll ◽  
Helen Müller ◽  
...  
Keyword(s):  
Solid State ◽  
Structure Determination ◽  
Solid State Nmr ◽  
Carbon Nitride ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
Theoretical Studies ◽  
X Ray ◽  
Important Intermediate

Graphitic carbon nitride modified with Pd nanoparticles toward efficient cathode catalyst for Li-O2 batteries

2020 ◽  
Vol 13 (07) ◽  
pp. 2051045
Author(s):  
Kaicheng Yue ◽  
Zhaoqian Yan ◽  
Zhihao Sun ◽  
Anran Li ◽  
Lei Qian
Keyword(s):  
Electron Microscope ◽  
Current Density ◽  
Carbon Nitride ◽  
Specific Capacity ◽  
Pd Nanoparticles ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
Cathode Catalyst ◽  
X Ray ◽  
Cathode Catalysts

In this work, graphitic carbon nitride (g-C3N4) was modified by Pd nanoparticles (Pd-CN) to prepare an efficient cathode catalyst for Li-O2 batteries. The specific surface area of g-C3N4 was improved to 239.56[Formula: see text]m2/g by two-steps thermal polymerization. Pd nanoparticles were loaded onto the g-C3N4 by K2PdCl4 reduction with NaBH4. The resulted Pd-CN composites were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscope, and transmission electron microscope. The results proved that g-C3N4 showed three-dimensional layered and porous structure, and Pd nanoparticles were successfully supported on it. The Li-O2 batteries using Pd-CN composites as cathode catalysts were assembled and tested. The maximum initial discharge specific capacity reached 26,614[Formula: see text]mAh[Formula: see text]g[Formula: see text] at current density of 100[Formula: see text]mA[Formula: see text]g[Formula: see text]. The electrodes remained large capacity under high current density, meaning excellent rate capability. Li-O2 batteries containing Pd-CN cathode were continuously cycled for 70 cycles with no loss of capacity and obvious change in the terminal voltage. These electrochemical results indicated that the loading Pd nanoparticles effectively increased specific capacity, reduced overpotential and improved the cyclic stability. The Pd-CN composites are proved to be the promising cathode catalysts for Li-O2 batteries.

scholarly journals Zirconia nanoparticle-modified graphitic carbon nitride nanosheets for effective photocatalytic degradation of 4-nitrophenol in water

2019 ◽  
Vol 9 (8) ◽  
Author(s):  
Mohanna Zarei ◽  
Jamil Bahrami ◽  
Mohammad Zarei
Keyword(s):  
Photocatalytic Activity ◽  
Photocatalytic Degradation ◽  
Carbon Nitride ◽  
Diffuse Reflectance Spectroscopy ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zirconia Nanoparticle ◽  
Carbon Nitride Nanosheets

Abstract Zirconia (ZrO2)-modified graphitic carbon nitride (g-C3N4) nanocomposite was used for effective photodegradation of 4-nitrophenol (4-NP) in water. The ZrO2 nanoparticles, g-C3N4 nanosheets, and ZrO2/g-C3N4 nanocomposite were well characterized by including N2 adsorption, X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, UV–Vis diffuse reflectance spectroscopy, photoelectrochemical measurements, and photoluminescence spectroscopy methods. ZrO2/g-C3N4 nanocomposites were formed at room temperature using sonication and used for effective for photodegradation of 4-NP under irradiation with visible light. The nanocomposite samples resulted in a significant increase in photocatalytic activity compared with single-component samples of g-C3N4. In particular, the ZrO2/g-C3N4 nanocomposite exhibited the significant increase in the photocatalytic activity. The ZrO2/g-C3N4 nanocomposite showed an excellent catalytic activity toward the reduction of 4-NP in aqueous medium. Further, ZrO2/g-C3N4 nanocomposite can be reused several times for photocatalytic degradation as well as for 4-NP adsorption.

Preparation of Nitrogen-Deficient Graphitic Carbon Nitride with a Large Specific Surface Area by Melt Pretreatment and Its Photocatalytic Performance

NANO ◽  
2020 ◽  
Vol 15 (06) ◽  
pp. 2050079
Author(s):  
Xuelei Li ◽  
Jinfeng Bai ◽  
Jiaqi Li ◽  
Chao Li ◽  
Junru Zhang ◽  
...  
Keyword(s):  
Visible Light ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Nitride ◽  
Mesoporous Structure ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
Large Specific Surface Area ◽  
X Ray

In this study, nitrogen-deficient graphitic carbon nitride (M-LS-g-C3N4) with a mesoporous structure and a large specific surface area was obtained by calcination after melt pretreatment using urea as a precursor. X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption, X-ray photoelectron spectroscopy (XPS), UV-Vis, ESR and photoluminescence (PL) were used to characterize the structure, morphology and optical performance of the samples. The TEM results showed the formation of a mesoporous structure on the 0.1[Formula: see text]M-LS-g-C3N4 surface. The porous structure led to an increase in the specific surface area from 41.5[Formula: see text]m2/g to 124.3[Formula: see text]m2/g. The UV-Vis results showed that nitrogen vacancies generated during the modification process reduced the band gap of g-C3N4 and improved the visible light absorption. The PL spectra showed that the nitrogen defects promoted the separation of photogenerated electron–hole pairs. In the visible light degradation of methyl orange (MO), the reaction rate constant of 0.1[Formula: see text]M-LS-g-C3N4 reached 0.0086[Formula: see text][Formula: see text], which was 5.05 times that of pure g-C3N4. Superoxide radicals and photogenerated holes were found to be the main active species in the reaction system. This study provides an efficient, green and convenient means of preparing graphitic carbon nitride with a large specific surface area.

scholarly journals Exploiting the Synergy of Powder X-ray Diffraction and Solid-State NMR Spectroscopy in Structure Determination of Organic Molecular Solids

2013 ◽  
Vol 117 (23) ◽  
pp. 12258-12265 ◽  
Author(s):  
Dmytro V. Dudenko ◽  
P. Andrew Williams ◽  
Colan E. Hughes ◽  
Oleg N. Antzutkin ◽  
Sitaram P. Velaga ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Structure Determination ◽  
Solid State Nmr ◽  
Molecular Solids ◽  
X Ray Diffraction ◽  
X Ray ◽  
Solid State Nmr Spectroscopy

scholarly journals Sugarcane juice derived carbon dot–graphitic carbon nitride composites for bisphenol A degradation under sunlight irradiation

2018 ◽  
Vol 9 ◽  
pp. 353-363 ◽  
Author(s):  
Lan Ching Sim ◽  
Jing Lin Wong ◽  
Chen Hong Hak ◽  
Jun Yan Tai ◽  
Kah Hon Leong ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Bisphenol A ◽  
Carbon Nitride ◽  
Separation Efficiency ◽  
Sugarcane Juice ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
Dominant Factor ◽  
Spectroscopic Techniques ◽  
X Ray

Carbon dots (CDs) and graphitic carbon nitride (g-C3N4) composites (CD/g-C3N4) were successfully synthesized by a hydrothermal method using urea and sugarcane juice as starting materials. The chemical composition, morphological structure and optical properties of the composites and CDs were characterized using various spectroscopic techniques as well as transmission electron microscopy. X-ray photoelectron spectroscopy (XPS) results revealed new signals for carbonyl and carboxyl groups originating from the CDs in CD/g-C3N4 composites while X-ray diffraction (XRD) results showed distortion of the host matrix after incorporating CDs into g-C3N4. Both analyses signified the interaction between g-C3N4 and CDs. The photoluminescence (PL) analysis indicated that the presence of too many CDs will create trap states at the CD/g-C3N4 interface, decelerating the electron (e−) transport. However, the CD/g-C3N4(0.5) composite with the highest coverage of CDs still achieved the best bisphenol A (BPA) degradation rate at 3.87 times higher than that of g-C3N4. Hence, the charge separation efficiency should not be one of the main factors responsible for the enhancement of the photocatalytic activity of CD/g-C3N4. Instead, the light absorption capability was the dominant factor since the photoreactivity correlated well with the ultraviolet–visible diffuse reflectance spectra (UV–vis DRS) results. Although the CDs did not display upconversion photoluminescence (UCPL) properties, the π-conjugated CDs served as a photosensitizer (like organic dyes) to sensitize g-C3N4 and injected electrons to the conduction band (CB) of g-C3N4, resulting in the extended absorption spectrum from the visible to the near-infrared (NIR) region. This extended spectral absorption allows for the generation of more electrons for the enhancement of BPA degradation. It was determined that the reactive radical species responsible for the photocatalytic activity were the superoxide anion radical (O2 •−) and holes (h+) after performing multiple scavenging tests.

Silver-mediated Bi2O3 and graphitic carbon nitride nanocomposite as all solid state Z scheme photocatalyst for imidacloprid pesticide abatement from water

2019 ◽  
Vol 171 ◽  
pp. 344-355 ◽  
Author(s):  
Pankaj Raizada ◽  
Anita Sudhaik ◽  
Pardeep Singh ◽  
Ahmad Hosseini-Bandegharaei ◽  
Vinod Kumar Gupta ◽  
...  
Keyword(s):  
Solid State ◽  
Carbon Nitride ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride

scholarly journals Influence of High Temperature Synthesis on the Structure of Graphitic Carbon Nitride and Its Hydrogen Generation Ability

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2756 ◽  
Author(s):  
Emilia Alwin ◽  
Kamila Kočí ◽  
Robert Wojcieszak ◽  
Michał Zieliński ◽  
Miroslava Edelmannová ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Carbon Nitride ◽  
Hydrogen Generation ◽  
Thermal Polymerization ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
Photocatalytic Decomposition ◽  
Heating Rates ◽  
X Ray ◽  
Synthesis Conditions

Graphitic carbon nitride (g-C3N4) was obtained by thermal polymerization of dicyandiamide, thiourea or melamine at high temperatures (550 and 600 °C), using different heating rates (2 or 10 °C min−1) and synthesis times (0 or 4 h). The effects of the synthesis conditions and type of the precursor on the efficiency of g-C3N4 were studied. The most efficient was the synthesis from dicyandiamide, 53%, while the efficiency in the process of synthesis from melamine and thiourea were much smaller, 26% and 11%, respectively. On the basis of the results provided by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (FTIR), ultraviolet–visible spectroscopy (UV–vis), thermogravimetric analysis (TGA), elemental analysis (EA), the best precursor and the optimum conditions of synthesis of g-C3N4 were identified to get the product of the most stable structure, the highest degree of ordering and condensation of structure and finally the highest photocatalytic activity. It was found that as the proton concentration decreased and the degree of condensation increased, the hydrogen yields during the photocatalytic decomposition of water–methanol solution were significantly enhanced. The generation of hydrogen was 1200 µmol g−1 and the selectivity towards hydrogen of more than 98%.

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