scholarly journals Mechanochemically Synthetized PAN-Based Co-N-Doped Carbon Materials as Electrocatalyst for Oxygen Evolution Reaction

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 290
Author(s):  
Paulette Gómez-López ◽  
José Ángel Salatti-Dorado ◽  
Daily Rodríguez-Padrón ◽  
Manuel Cano ◽  
Clemente G. Alvarado-Beltrán ◽  
...  

We report a new class of polyacrylonitrile (PAN)-based Co-N-doped carbon materials that can act as suitable catalyst for oxygen evolution reactions (OER). Different Co loadings were mechanochemically added into post-consumed PAN fibers. Subsequently, the samples were treated at 300 °C under air (PAN-A) or nitrogen (PAN-N) atmosphere to promote simultaneously the Co3O4 species and PAN cyclization. The resulting electrocatalysts were fully characterized and analyzed by X-ray diffraction (XRD) and photoelectron spectroscopy (XPS), transmission (TEM) and scanning electron (SEM) microscopies, as well as nitrogen porosimetry. The catalytic performance of the Co-N-doped carbon nanomaterials were tested for OER in alkaline environments. Cobalt-doped PAN-A samples showed worse OER electrocatalytic performance than their homologous PAN-N ones. The PAN-N/3% Co catalyst exhibited the lowest OER overpotential (460 mV) among all the Co-N-doped carbon nanocomposites, reaching 10 mA/cm2. This work provides in-depth insights on the electrocatalytic performance of metal-doped carbon nanomaterials for OER.

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2163 ◽  
Author(s):  
Yuliya V. Fedoseeva ◽  
Egor V. Lobiak ◽  
Elena V. Shlyakhova ◽  
Konstantin A. Kovalenko ◽  
Viktoriia R. Kuznetsova ◽  
...  

Highly porous nitrogen-doped carbon nanomaterials have distinct advantages in energy storage and conversion technologies. In the present work, hydrothermal treatments in water or ammonia solution were used for modification of mesoporous nitrogen-doped graphitic carbon, synthesized by deposition of acetonitrile vapors on the pyrolysis products of calcium tartrate. Morphology, composition, and textural characteristics of the original and activated materials were studied by transmission electron microscopy, X-ray photoelectron spectroscopy, near-edge X-ray absorption fine structure spectroscopy, infrared spectroscopy, and nitrogen gas adsorption method. Both treatments resulted in a slight increase in specific surface area and volume of micropores and small mesopores due to the etching of carbon surface. Compared to the solely aqueous medium, activation with ammonia led to stronger destruction of the graphitic shells, the formation of larger micropores (1.4 nm vs. 0.6 nm), a higher concentration of carbonyl groups, and the addition of nitrogen-containing groups. The tests of nitrogen-doped carbon materials as electrodes in 1M H2SO4 electrolyte and sodium-ion batteries showed improvement of electrochemical performance after hydrothermal treatments especially when ammonia was used. The activation method developed in this work is hopeful to open up a new route of designing porous nitrogen-doped carbon materials for electrochemical applications.


Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 530 ◽  
Author(s):  
Chaoqun Bian ◽  
Xiao Wang ◽  
Lan Yu ◽  
Fen Zhang ◽  
Jie Zhang ◽  
...  

The incorporation of metal heteroatoms into zeolites is an effective modification strategy for enhancing their catalytic performance. Herein, for the first time we report a generalized methodology for inserting metal heteroatoms (such as Sn, Fe, Zn, and Co) into the layered zeolite precursor RUB-36 via interlayer expansion by using the corresponding metal acetylacetate salt. Through this generalized methodology, Sn-JHP-1, Fe-JHP-1, Zn-JHP-1 and Co-JHP-1 zeolites could be successfully prepared by the reaction of RUB-36 and corresponding metal acetylacetate salt at 180 °C for 24 h in the presence of HCl solution. As a typical example, Sn-JHP-1 and calcined Sn-JHP-1 (Sn-JHP-2) zeolite is well characterized by the X-ray diffraction (XRD), diffuse reflectance ultraviolet-visible (UV-Vis), inductively coupled plasma (ICP), N2 sorption, temperature-programmed-desorption of ammonia (NH3-TPD) and X-ray photoelectron spectroscopy (XPS) techniques, which confirm the expansion of adjacent interlayers and thus the incorporation of isolated Sn sites within the zeolite structure. Notably, the obtained Sn-JHP-2 zeolite sample shows enhanced catalytic performance in the conversion of glucose to levulinic acid (LA) reaction.


Molecules ◽  
2019 ◽  
Vol 24 (15) ◽  
pp. 2695 ◽  
Author(s):  
Mhadmhan ◽  
Marquez-Medina ◽  
Romero ◽  
Reubroycharoen ◽  
Luque

We have successfully incorporated iron species into mesoporous aluminosilicates (AlSBA15) using a simple mechanochemical milling method. The catalysts were characterized by nitrogen physisorption, inductively coupled plasma mass spectrometry (ICP-MS), pyridine (PY) and 2,6-dimethylpyridine (DMPY) pulse chromatography titration, powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX). The catalysts were tested in the N-alkylation reaction of aniline with benzyl alcohol for imine production. According to the results, the iron sources, acidity of catalyst and reaction conditions were important factors influencing the reaction. The catalyst showed excellent catalytic performance, achieving 97% of aniline conversion and 96% of imine selectivity under optimized conditions.


2021 ◽  
Author(s):  
Yu Fan ◽  
Yan-ning Yang ◽  
Chen Ding

Abstract The g-C3N4 nanosheet was prepared by calcination method, the MoS2 nanosheet was prepared by hydrothermal method. The g-C3N4/MoS2 composites were prepared by ultrasonic composite in anhydrous ethanol. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible spectroscopy (UV-Vis), and photoluminescence (PL) techniques were used to characterize the materials. The photocatalytic degradation of Rhodamine B (Rh B) by g-C3N4/MoS2 composites with different mass ratios was investigated under visible light. The results show that a small amount of MoS2 combined with g-C3N4 can significantly improve photocatalytic activity. The g-C3N4/MoS2 composite with a mass ratio of 1:8 has the highest photocatalytic activity, and the degradation rate of Rh B increases from 50% to 99.6%. The main reason is that MoS2 and g-C3N4 have a matching band structure. The separation rate of photogenerated electron-hole pairs is enhanced. So the g-C3N4/MoS2 composite can improve the photocatalytic activity. The photocatalytic mechanism was proposed through the active matter capture experiment.


2019 ◽  
Vol 6 (3) ◽  
pp. 181422
Author(s):  
Xingchen Liu ◽  
SuZhen Wang ◽  
Song Wang ◽  
Han Shi ◽  
Xiaolong Zhang ◽  
...  

The three-dimensional flower-like Bi 2 WO 6 was synthesized through a one-step microwave method (the reaction temperature was 434 K and the reaction took 10 min) with the assistance of ethanolamine (EA). The prepared samples were characterized by X-ray diffraction, scanning electron microscopy, Fourier-transform infrared spectroscopy, ultraviolet–visible spectroscopy, PL, X-ray photoelectron spectroscopy and Brunauer–Emmett–Teller analysis. Methyl orange was used as target pollutant to evaluate the photocatalysis property of samples. Furthermore, the influence of the mechanism of EA on the structure and catalytic performance of Bi 2 WO 6 was discussed. The detailed characterizations revealed that the three-dimensional flower-like Bi 2 WO 6 was successfully synthesized with the assistance of EA. The results confirmed that EA significantly influenced the morphology of Bi 2 WO 6 products. The addition of EA can effectively alter the pressure of the reaction and improve the crystal phase and structure of Bi 2 WO 6 photocatalysts, enhancing the photocatalytic activity of samples and improving the photocatalytic efficiency. EA can serve as an assembling agent and structure-directing agent resulting in the formation of flower-like architectures. With the increase of the amount of EA, the as-prepared Bi 2 WO 6 sample gradually forms a flower-like structure, leading to a shorter time of light holes migrating to the surface of the catalyst. It makes the compound rate significantly decreased, and improves the photocatalytic efficiency of the sample.


2020 ◽  
Vol 10 (5) ◽  
pp. 726-731
Author(s):  
Bin Zeng ◽  
Wujun Zeng

Introduction: Solid porous carbon (SPC) with micro-mesopore structures was successfully fabricated from used cigarette filters via carbonization. Experimental: The morphology and structure of the as-prepared porous carbon materials were characterized using X-ray diffraction, Fourier-transform infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. Results: This novel carbon material allows the removal of organic pollutants from water. The maximum adsorbed capacity of methylene blue could reach ~185 mg.g-1, which was attributed to the high specific surface area (567.7 m2.g-1) and the micro-mesoporous structure of the samples. Conclusion: Furthermore, when genomic stability was maintained in the solution, SPC was easily extracted. The mechanism for the fabrication of the proposed used cigarette filter is elucidated in this study.


Catalysts ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 378 ◽  
Author(s):  
Junjing Li ◽  
Huan Wang ◽  
Liang Wang ◽  
Chang Ma ◽  
Cong Luan ◽  
...  

Noble metal palladium modified foamed nickel electrode (Pd/foam-Ni) was prepared by electrodeposition method. The fabricated electrode showed better catalytic performance than the Pd/foam-Ni prepared by conventional electroless deposition. The catalysts were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). Electrocatalytic activity of the Pd/Ni was studied for the hydrodechlorination of monochlorophenol isomers. The Pd/Ni exhibited good catalytic activity for 3-chlorophenol (3-CP). Complete decomposition of chlorophenol isomers could be achieved within 2 h, and the hydrodechlorination process conformed to the pseudo-first-order kinetic model. It showed a supreme stability after recycling for 5 times. The Pd/Ni exhibited a promising application prospect with high effectiveness and low Pd loading.


Catalysts ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 85 ◽  
Author(s):  
Pan Gao ◽  
Mengjie Hao ◽  
Yue He ◽  
Yuan Song ◽  
Shaoxia Yang

Fe2O3–ZrO2 catalysts with different morphologies (nanoplates (HZNPs), nanorods (HZNRs), nanocubes (HZNCs), and nanotubes (HZNTs)) were prepared by a hydrothermal method to investigate the effect of the morphology on the catalytic performance in the Fenton-like reaction for sulfamethazine (SMT) degradation. The Fe2O3–ZrO2 catalysts were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Brunauer–Emmett–Teller (BET) analysis. The H2O2 adsorption and the Fe2+ density sites on the Fe2O3–ZrO2 catalysts had a close relationship with the morphologies and exhibited an important effect on the ·OH formation in the Fenton-like reaction. Free ·OH radicals were the main oxidative species in the reaction, and the normalized ·OH concentration per surface area of the catalysts was 4.52, 2.24, 2.20, and 0.37 μmol/m2 for HZNPs, HZNRs, HZNCs, and HZNTs, respectively. The Fe2O3–ZrO2 catalysts with different morphologies showed good catalytic performance, and the order of SMT degradation was HZNPs > HZNRs > HZNCs > HZNTs. Total SMT removal was achieved in the Fenton-like reaction over HZNPs at pH 3.0 and 45 °C after 240 min.


Author(s):  
Alessio Zuliani ◽  
Manuel Cano ◽  
Federica Calsolaro ◽  
Alain R. Puente Santiago ◽  
Juan J. Giner-Casares ◽  
...  

Microwave and ultrasound preparation of highly active OER electrodes derived from pinecones and having a low cobalt content is reported.


Nanomaterials ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 877 ◽  
Author(s):  
Guangyu Lei ◽  
Jingwen Ma ◽  
Zhen Li ◽  
Xiaobin Fan ◽  
Wenchao Peng ◽  
...  

In this paper, a facile route has been developed to prepare magnetic trimetallic Au-Ag-γ-Fe2O3/rGO nanocomposites. The impact of the preparation method (the intensity of reductant) on the catalytic performance was investigated. The nanocomposites were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The prepared nanocomposites show fine catalytic activity towards the reduction reaction of 4-nitrophenol (4-NP). The nanocomposites also have superparamagnetism at room temperature, which can be easily separated from the reaction systems by applying an external magnetic field.


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