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12 pages, 2531 KiB

Open AccessArticle

Structural Investigation of the Synthesized Few-Layer Graphene from Coal under Microwave

by Faridul Islam, Arash Tahmasebi, Behdad Moghtaderi and Jianglong Yu

Nanomaterials 2022, 12(1), 57; https://doi.org/10.3390/nano12010057 - 26 Dec 2021

Cited by 12 | Viewed by 2770

This study focused on the structural investigation of few-layer graphene (FLG) synthesis from bituminous coal through a catalytic process under microwave heat treatment (MW). The produced FLG has been examined by Raman spectroscopy, XRD, TEM, and AFM. Coal was activated using the potassium [...] Read more.

This study focused on the structural investigation of few-layer graphene (FLG) synthesis from bituminous coal through a catalytic process under microwave heat treatment (MW). The produced FLG has been examined by Raman spectroscopy, XRD, TEM, and AFM. Coal was activated using the potassium hydroxide activation process. The FLG synthesis processing duration was much faster requiring only 20 min under the microwave radiation. To analyse few-layer graphene samples, we considered the three bands, i.e., D, G, and 2D, of Raman spectra. At 1300 °C, the P10% Fe sample resulted in fewer defects than the other catalyst percentages sample. The catalyst percentages affected the structural change of the FLG composite materials. In addition, the Raman mapping showed that the catalyst loaded sample was homogeneously distributed and indicated a few-layer graphene sheet. In addition, the AFM technique measured the FLG thickness around 4.5 nm. Furthermore, the HRTEM images of the P10% Fe sample contained a unique morphology with 2–7 graphitic layers of graphene thin sheets. This research reported the structural revolution with latent feasibility of FLG synthesis from bituminous coal in a wide range. Full article

(This article belongs to the Special Issue Carbon-Doped Nanocomposites for Catalytical Application)

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12 pages, 6657 KiB

Open AccessArticle

High-Level Oxygen Reduction Catalysts Derived from the Compounds of High-Specific-Surface-Area Pine Peel Activated Carbon and Phthalocyanine Cobalt

by Lei Zhao, Ziwei Lan, Wenhao Mo, Junyu Su, Huazhu Liang, Jiayu Yao and Wenhu Yang

Nanomaterials 2021, 11(12), 3429; https://doi.org/10.3390/nano11123429 - 17 Dec 2021

Cited by 4 | Viewed by 2315

Abstract

Non-platinum carbon-based catalysts have attracted much more attention in recent years because of their low cost and outstanding performance, and are regarded as one of the most promising alternatives to precious metal catalysts. Activated carbon (AC), which has a large specific surface area [...] Read more.

Non-platinum carbon-based catalysts have attracted much more attention in recent years because of their low cost and outstanding performance, and are regarded as one of the most promising alternatives to precious metal catalysts. Activated carbon (AC), which has a large specific surface area (SSA), can be used as a carrier or carbon source at the same time. In this work, stable pine peel bio-based materials were used to prepare large-surface-area activated carbon and then compound with cobalt phthalocyanine (CoPc) to obtain a high-performance cobalt/nitrogen/carbon (Co-N-C) catalyst. High catalytic activity is related to increasing the number of Co particles on the large-specific-area activated carbon, which are related with the immersing effect of CoPc into the AC and the rational decomposed temperature of the CoPc ring. The synergy with N promoting the exposure of CoN_x active sites is also important. The E_onset of the catalyst treated with a composite proportion of AC and CoPc of 1 to 2 at 800 °C (AC@CoPc-800-1-2) is 1.006 V, higher than the Pt/C (20 wt%) catalyst. Apart from this, compared with other AC/CoPc series catalysts and Pt/C (20 wt%) catalyst, the stability of AC/CoPc-800-1-2 is 87.8% in 0.1 M KOH after 20,000 s testing. Considering the performance and price of the catalyst in a practical application, these composite catalysts combining biomass carbon materials with phthalocyanine series could be widely used in the area of catalysts and energy storage. Full article

(This article belongs to the Special Issue Carbon-Doped Nanocomposites for Catalytical Application)

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10 pages, 2413 KiB

Open AccessArticle

Ultrahigh-Pressure Preparation and Catalytic Activity of MOF-Derived Cu Nanoparticles

by Ichiro Yamane, Kota Sato, Ryoichi Otomo, Takashi Yanase, Akira Miura, Taro Nagahama, Yuichi Kamiya and Toshihiro Shimada

Nanomaterials 2021, 11(4), 1040; https://doi.org/10.3390/nano11041040 - 19 Apr 2021

Cited by 10 | Viewed by 2752

Abstract

A metal–organic framework (MOF) consisting of Cu-benzenetricarboxylic acid was processed under ultrahigh pressure (5 GPa) and at temperature of up to 500 °C. The products were characterized with TEM, FTIR, and XAFS. The decomposition of the MOF started at 200 °C at 5 [...] Read more.

A metal–organic framework (MOF) consisting of Cu-benzenetricarboxylic acid was processed under ultrahigh pressure (5 GPa) and at temperature of up to 500 °C. The products were characterized with TEM, FTIR, and XAFS. The decomposition of the MOF started at 200 °C at 5 GPa. This temperature was much lower than that in the vacuum. Single-nanometer Cu nanoparticles were obtained in carbon matrix, which was significantly smaller than the Cu particles prepared at ambient pressure. The catalytic activity for Huisgen cycloaddition was examined, and the sample processed at 5 GPa showed a much improved performance compared with that of the MOF-derived Cu nanoparticles prepared without high pressure. Full article

(This article belongs to the Special Issue Carbon-Doped Nanocomposites for Catalytical Application)

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