Catalysts

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9 pages, 1878 KiB

Open AccessFeature PaperArticle

Environmentally Friendly Route for Fabricating Conductive Agent for Lithium-Ion Batteries: Carbon Nanoparticles Derived from Polyethylene

by Jihye Mok, Dalsu Choi and Suk Ho Bhang

Catalysts 2021, 11(4), 424; https://doi.org/10.3390/catal11040424 - 26 Mar 2021

Cited by 3 | Viewed by 2267

Abstract

Here, we introduce an environmentally friendly way of fabricating carbon nanoparticles which can be utilized as conductive agent for lithium-ion batteries (LIBs). Polyethylene (PE), which comprises the largest portion of plastic waste, was used as a source for carbon nanoparticle synthesis. Sulfonation allowed [...] Read more.

Here, we introduce an environmentally friendly way of fabricating carbon nanoparticles which can be utilized as conductive agent for lithium-ion batteries (LIBs). Polyethylene (PE), which comprises the largest portion of plastic waste, was used as a source for carbon nanoparticle synthesis. Sulfonation allowed chemical structural transformation of innately non-carbonizable PE into a carbonizable conformation, and carbon nanoparticles could be successfully derived from sulfonated PE. Then, PE-derived carbon nanoparticles were used as conductive agents for LIBs, and assembled cells exhibited stable performance. Even though the performance is not as good as Super-P, utilization of PE as a source of conductive agent for LIBs might provide an economical advantage to upcycle PE. Full article

(This article belongs to the Special Issue Environmentally Friendly Applications of Nanocatalysts)

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12 pages, 3824 KiB

Open AccessArticle

Synthesis of Au–Cu Alloy Nanoparticles as Peroxidase Mimetics for H₂O₂ and Glucose Colorimetric Detection

by Cun Liu, Sang Hyuk Im and Taekyung Yu

Catalysts 2021, 11(3), 343; https://doi.org/10.3390/catal11030343 - 7 Mar 2021

Cited by 21 | Viewed by 3355

Abstract

The detection of hydrogen peroxide (H₂O₂) is essential in many research fields, including medical diagnosis, food safety, and environmental monitoring. In this context, Au-based bimetallic alloy nanomaterials have attracted increasing attention as an alternative to enzymes due to their [...] Read more.

The detection of hydrogen peroxide (H₂O₂) is essential in many research fields, including medical diagnosis, food safety, and environmental monitoring. In this context, Au-based bimetallic alloy nanomaterials have attracted increasing attention as an alternative to enzymes due to their superior catalytic activity. In this study, we report a coreduction synthesis of gold–copper (Au–Cu) alloy nanoparticles in aqueous phase. By controlling the amount of Au and Cu precursors, the Au/Cu molar ratio of the nanoparticles can be tuned from 1/0.1 to 1/2. The synthesized Au–Cu alloy nanoparticles show good peroxidase-like catalytic activity and high selectivity for the H₂O₂-mediated oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB, colorless) to TMB oxide (blue). The Au–Cu nanoparticles with an Au/Cu molar ratio of 1/2 exhibit high catalytic activity in the H₂O₂ colorimetric detection, with a limit of detection of 0.141 μM in the linear range of 1–10 μM and a correlation coefficient R² = 0.991. Furthermore, the Au–Cu alloy nanoparticles can also efficiently detect glucose in the presence of glucose oxidase (GOx), and the detection limit is as low as 0.26 μM. Full article

(This article belongs to the Special Issue Environmentally Friendly Applications of Nanocatalysts)

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8 pages, 1599 KiB

Open AccessFeature PaperArticle

Facile Aqueous–Phase Synthesis of Pd–FePt Core–Shell Nanoparticles for Methanol Oxidation Reaction

by Xiangyun Xiao, Euiyoung Jung, Sehyun Yu, Hyeonjin Kim, Hong-Kyu Kim, Kwan-Young Lee, Jae-Pyoung Ahn, Taeho Lim, Jinheung Kim and Taekyung Yu

Catalysts 2021, 11(1), 130; https://doi.org/10.3390/catal11010130 - 16 Jan 2021

Cited by 2 | Viewed by 2372

Abstract

Multi-metallic Pd@FePt core–shell nanoparticles were synthesized using a direct seed-mediated growth method, consisting of facile and mild procedures, to increase yield. The Fe/Pt ratio in the shell was easily controlled by adjusting the amount of Fe and Pt precursors. Furthermore, compared with commercial [...] Read more.

Multi-metallic Pd@FePt core–shell nanoparticles were synthesized using a direct seed-mediated growth method, consisting of facile and mild procedures, to increase yield. The Fe/Pt ratio in the shell was easily controlled by adjusting the amount of Fe and Pt precursors. Furthermore, compared with commercial Pt/C catalysts, Pd@FePt nanoparticles exhibited excellent activity and stability toward the methanol oxidation reaction (MOR), making them efficient in direct methanol fuel cells (DMFC). Full article

(This article belongs to the Special Issue Environmentally Friendly Applications of Nanocatalysts)

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10 pages, 979 KiB

Open AccessFeature PaperArticle

Catalytic Hydrogenation and Dehydrogenation Reactions of N-alkyl-bis(carbazole)-Based Hydrogen Storage Materials

by Joori Jung, Byeong Soo Shin, Jeong Won Kang and Won-Sik Han

Catalysts 2021, 11(1), 123; https://doi.org/10.3390/catal11010123 - 15 Jan 2021

Cited by 4 | Viewed by 3502

Abstract

Recently, there have been numerous efforts to develop hydrogen-rich organic materials because hydrogen energy is emerging as a renewable energy source. In this regard, we designed and prepared four new materials based on N-alkyl-bis(carbazole), 9,9′-(2-methylpropane-1,3-diyl)bis(9H-carbazole) (MBC), 9,9′-(2-ethylpropane-1,3-diyl)bis(9H [...] Read more.

Recently, there have been numerous efforts to develop hydrogen-rich organic materials because hydrogen energy is emerging as a renewable energy source. In this regard, we designed and prepared four new materials based on N-alkyl-bis(carbazole), 9,9′-(2-methylpropane-1,3-diyl)bis(9H-carbazole) (MBC), 9,9′-(2-ethylpropane-1,3-diyl)bis(9H-carbazole) (EBC), 9,9′-(2-propylpropane-1,3-diyl)bis(9H-carbazole) (PBC), and 9,9′-(2-butylpropane-1,3-diyl)bis(9H-carbazole) (BBC), to investigate their hydrogen adsorption/hydrogen desorption reactivity depending on the length of the alkyl chain. The gravimetric densities of MBC, EBC, PBC, and BBC were 5.86, 5.76, 5.49, and 5.31 H₂ wt %, respectively, again depending on the alkyl chain length. All materials showed complete hydrogenation reactions under ruthenium on an alumina catalyst at 190 °C, and complete reverse reactions and dehydrogenation reactions were observed under palladium on an alumina catalyst at <280 °C. At this temperature, all the prepared compounds were thermally stable, and no decomposition was observed. Full article

(This article belongs to the Special Issue Environmentally Friendly Applications of Nanocatalysts)

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8 pages, 1600 KiB

Open AccessFeature PaperArticle

Facile Aqueous-Phase Synthesis of Stabilizer-Free Photocatalytic Nanoparticles

by Hyein Lee, Sung-Soo Kim, Suk Ho Bhang and Taekyung Yu

Catalysts 2021, 11(1), 111; https://doi.org/10.3390/catal11010111 - 14 Jan 2021

Cited by 2 | Viewed by 1916

Abstract

One of the challenges of using nanoparticles as catalysts is the presence of reaction-disturbing stabilizers that surround the nanoparticle surface. In this report, we demonstrate a method to synthesize stabilizer-free bismuth oxychloride (BiOCl) nanoparticles to increase photocatalytic activity. This synthesis method is remarkably [...] Read more.

One of the challenges of using nanoparticles as catalysts is the presence of reaction-disturbing stabilizers that surround the nanoparticle surface. In this report, we demonstrate a method to synthesize stabilizer-free bismuth oxychloride (BiOCl) nanoparticles to increase photocatalytic activity. This synthesis method is remarkably simple, involving only BiCl₃ and deionized water. After heating an aqueous solution containing BiCl₃, plate-shaped BiOCl nanoparticles were formed. The stabilizer-free BiOCl nanoplates exhibited higher photocatalytic activities compared to polyvinylpyrrolidone- and polyethyleneimine-stabilized nanoplates for the degradation of methylene blue. Full article

(This article belongs to the Special Issue Environmentally Friendly Applications of Nanocatalysts)

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15 pages, 6991 KiB

Open AccessArticle

Pt Nanoclusters Anchored on Hollow Ag-Au Nanostructures for Electrochemical Oxidation of Methanol

by Xinghe Li, Xinyu Qin, Bingyi Yan, Huiling Huang, Wang Zhang and Yuanzhe Piao

Catalysts 2020, 10(12), 1440; https://doi.org/10.3390/catal10121440 - 9 Dec 2020

Cited by 8 | Viewed by 2137

Abstract

The synthetic method of Pt nanocluster-anchored hollow Ag-Au nanostructures and measurements of their electrocatalytic properties for methanol oxidation reaction (MOR) are reported here. In this synthesis, uniform Ag nanospheres were prepared by reduction of silver nitrate (AgNO₃) with sodium borohydride (NaBH [...] Read more.

The synthetic method of Pt nanocluster-anchored hollow Ag-Au nanostructures and measurements of their electrocatalytic properties for methanol oxidation reaction (MOR) are reported here. In this synthesis, uniform Ag nanospheres were prepared by reduction of silver nitrate (AgNO₃) with sodium borohydride (NaBH₄) and then hollow Ag-Au nanostructures were synthesized via galvanic replacement of the as-prepared Ag nanospheres with Au³⁺. Finally, the reduction of potassium tetrachloroplatinate (II) (K₂PtCl₄) with ascorbic acid was performed to deposit Pt nanoclusters on the surface of hollow Ag-Au nanostructures. The hollow interior of Pt nanocluster-anchored Ag-Au nanostructures and change in the size of Pt nanoclusters by varying the injected molar ratio of Pt/Au were observed by transmission electron microscopy (TEM). Moreover, other morphological, compositional, and optical information of the obtained nanoscale materials were analyzed by X-ray diffraction analysis (XRD), inductively coupled plasma mass spectrometry (ICP-MS), and ultraviolet-visible spectroscopy (UV-vis). The electrocatalytic ability of the obtained Pt nanocluster-anchored hollow Ag-Au nanostructures toward MOR was confirmed by the results of cyclic voltametric (CV) measurements. The ease of three-step synthetic strategy and good electrocatalytic performance of the Pt nanocluster-anchored hollow Ag-Au nanostructures displayed their promising potential in the use of electrochemical oxidation of methanol. Full article

(This article belongs to the Special Issue Environmentally Friendly Applications of Nanocatalysts)

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8 pages, 7358 KiB

Open AccessFeature PaperArticle

Controlling the Degree of Coverage of the Pt Shell in Pd@Pt Core–Shell Nanocubes for Methanol Oxidation Reaction

by Xiangyun Xiao, Euiyoung Jung, Sehyun Yoo, Taeho Lim, Jinheung Kim and Taekyung Yu

Catalysts 2020, 10(10), 1133; https://doi.org/10.3390/catal10101133 - 1 Oct 2020

Cited by 4 | Viewed by 2377

Abstract

The synthesis of Pd@Pt core–shell nanocubes was achieved through a direct seed-mediated growth method. This process represents a simple and cost-effective way to produce core–shell nanocubes. The morphology of the Pd@Pt core–shell nanocubes varied from simple cubic to concave cubic, depending on the [...] Read more.

The synthesis of Pd@Pt core–shell nanocubes was achieved through a direct seed-mediated growth method. This process represents a simple and cost-effective way to produce core–shell nanocubes. The morphology of the Pd@Pt core–shell nanocubes varied from simple cubic to concave cubic, depending on the reducing agent and the Pt content. The selection of the reducing agent is important because the reduction rate is directly related to the shell growth. The catalytic activity and stability of the Pd@Pt core–shell nanocubes in the methanol oxidation reaction were different for the nanocubes with partial and full Pt shells. Full article

(This article belongs to the Special Issue Environmentally Friendly Applications of Nanocatalysts)

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14 pages, 8104 KiB

Open AccessFeature PaperArticle

Facile Direct Seed-Mediated Growth of AuPt Bimetallic Shell on the Surface of Pd Nanocubes and Application for Direct H₂O₂ Synthesis

by Geun-Ho Han, Ki Yoon Kim, Hyunji Nam, Hyeonjin Kim, Jihwan Yoon, Jung-Hyun Lee, Hong-Kyu Kim, Jae-Pyoung Ahn, Seung Yong Lee, Kwan-Young Lee and Taekyung Yu

Catalysts 2020, 10(6), 650; https://doi.org/10.3390/catal10060650 - 10 Jun 2020

Cited by 13 | Viewed by 3221

Abstract

The selective enhancement of catalytic activity is a challenging task, as catalyst modification is generally accompanied by both desirable and undesirable properties. For example, in the case of the direct synthesis of hydrogen peroxide, Pt on Pd improves hydrogen conversion, but lowers hydrogen [...] Read more.

The selective enhancement of catalytic activity is a challenging task, as catalyst modification is generally accompanied by both desirable and undesirable properties. For example, in the case of the direct synthesis of hydrogen peroxide, Pt on Pd improves hydrogen conversion, but lowers hydrogen peroxide selectivity, whereas Au on Pd enhances hydrogen peroxide selectivity but decreases hydrogen conversion. Toward an ideal catalytic property, the development of a catalyst that is capable of improving H-H dissociation for increasing H₂ conversion, whilst suppressing O-O dissociation for high H₂O₂ selectivity would be highly beneficial. Pd-core AuPt-bimetallic shell nanoparticles with a nano-sized bimetallic layer composed of Au-rich or Pt-rich content with Pd cubes were readily prepared via the direct seed-mediated growth method. In the Pd-core AuPt-bimetallic shell nanoparticles, Au was predominantly located on the {100} facets of the Pd nanocubes, whereas Pt was deposited on the corners of the Pd nanocubes. The evaluation of Pd-core AuPt-bimetallic shell nanoparticles with varying Au and Pt contents revealed that Pd-core AuPt-bimetallic shell that was composed of 2.5 mol% Au and 5 mol% Pt, in relation to Pd, exhibited the highest H₂O₂ production rate (914 mmol H₂O₂ g_metal⁻¹ h⁻¹), due to the improvement of both H₂O₂ selectivity and H₂ conversion. Full article

(This article belongs to the Special Issue Environmentally Friendly Applications of Nanocatalysts)

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