Nanomaterials

Research

18 pages, 19846 KiB

Open AccessArticle

Pd Nanocatalyst Adorning Coral Reef Nanocomposite for the Synthesis of Nitriles: Utility of Cucurbita pepo Leaf Extract as a Stabilizing and Reducing Agent

by Mahmoud Nasrollahzadeh, Fatemeh Ghorbannezhad, S. Mohammad Sajadi and Rajender S. Varma

Nanomaterials 2019, 9(4), 565; https://doi.org/10.3390/nano9040565 - 7 Apr 2019

Cited by 15 | Viewed by 3272

Abstract

A simple procedure for the palladium-catalyzed cyanation of aryl halides is described via a nucleophilic non-toxic cyanide source, K₄[Fe(CN)₆] in the presence of Pd/coral reef nanocomposite as a heterogeneous catalyst; the protocol provides a useful and easy method for [...] Read more.

A simple procedure for the palladium-catalyzed cyanation of aryl halides is described via a nucleophilic non-toxic cyanide source, K₄[Fe(CN)₆] in the presence of Pd/coral reef nanocomposite as a heterogeneous catalyst; the protocol provides a useful and easy method for the synthesis of aryl nitriles that are generated from the corresponding variant aryl halides, with sodium carbonate as a base. The nanocatalyst was prepared by a biological process using aqueous extract of leaves of Cucurbita pepo as a stabilizing and reducing agent and coral reef as a natural support, without deploying any hazardous chemicals. The catalyst, that is easily separable from the reaction mixture and reused multiple times, was characterized by FT-IR (Fourier-Transform Infrared Spectroscopy), ICP-AES (Inductively Coupled Plasma Atomic Emission Spectroscopy), XRD (X-ray Diffraction), TEM (Transmission Electron Microscopy), FE-SEM (Field Emission Scanning Electron Microscopy), EDS (Energy Dispersive X-ray Spectroscopy) and elemental mapping. Full article

(This article belongs to the Special Issue Sustainable Nanoparticles - Their Synthesis and Catalytic Applications)

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14 pages, 3345 KiB

Open AccessArticle

Mesoporous Graphitic Carbon Nitrides Decorated with Cu Nanoparticles: Efficient Photocatalysts for Degradation of Tartrazine Yellow Dye

by Tao Zhang, Isis P. A. F. Souza, Jiahe Xu, Vitor C. Almeida and Tewodros Asefa

Nanomaterials 2018, 8(9), 636; https://doi.org/10.3390/nano8090636 - 21 Aug 2018

Cited by 20 | Viewed by 4662

Abstract

A series of mesoporous graphitic carbon nitride (mpg-C₃N₄) materials are synthesized by directly pyrolyzing melamine containing many embedded silica nanoparticles templates, and then etching the silica templates from the carbonized products. The mass ratio of melamine-to-silica templates and the [...] Read more.

A series of mesoporous graphitic carbon nitride (mpg-C₃N₄) materials are synthesized by directly pyrolyzing melamine containing many embedded silica nanoparticles templates, and then etching the silica templates from the carbonized products. The mass ratio of melamine-to-silica templates and the size of the silica nanoparticles are found to dictate whether or not mpg-C₃N₄ with large surface area and high porosity form. The surfaces of the mpg-C₃N₄ materials are then decorated with copper (Cu) nanoparticles, resulting in Cu-decorated mpg-C₃N₄ composite materials that show excellent photocatalytic activity for degradation of tartrazine yellow dye. The materials’ excellent photocatalytic performance is attributed to their high surface area and the synergistic effects created in them by mpg-C₃N₄ and Cu nanoparticles, including the Cu nanoparticles’ greater ability to separate photogenerated charge carriers from mpg-C₃N₄. Full article

(This article belongs to the Special Issue Sustainable Nanoparticles - Their Synthesis and Catalytic Applications)

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17 pages, 3121 KiB

Open AccessArticle

Functionalized Tyrosinase-Lignin Nanoparticles as Sustainable Catalysts for the Oxidation of Phenols

by Eliana Capecchi, Davide Piccinino, Ines Delfino, Paolo Bollella, Riccarda Antiochia and Raffaele Saladino

Nanomaterials 2018, 8(6), 438; https://doi.org/10.3390/nano8060438 - 15 Jun 2018

Cited by 41 | Viewed by 6452

Abstract

Sustainable catalysts for the oxidation of phenol derivatives under environmentally friendly conditions were prepared by the functionalization of lignin nanoparticles with tyrosinase. Lignin, the most abundant polyphenol in nature, is the main byproduct in the pulp and paper manufacturing industry and biorefinery. Tyrosinase [...] Read more.

Sustainable catalysts for the oxidation of phenol derivatives under environmentally friendly conditions were prepared by the functionalization of lignin nanoparticles with tyrosinase. Lignin, the most abundant polyphenol in nature, is the main byproduct in the pulp and paper manufacturing industry and biorefinery. Tyrosinase has been immobilized by direct adsorption, encapsulation, and layer-by-layer deposition, with or without glutaraldehyde reticulation. Lignin nanoparticles were found to be stable to the tyrosinase activity. After the enzyme immobilization, they showed a moderate to high catalytic effect in the synthesis of catechol derivatives, with the efficacy of the catalyst being dependent on the specific immobilization procedures. Full article

(This article belongs to the Special Issue Sustainable Nanoparticles - Their Synthesis and Catalytic Applications)

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10 pages, 1319 KiB

Open AccessArticle

Borylation of α,β-Unsaturated Acceptors by Chitosan Composite Film Supported Copper Nanoparticles

by Wu Wen, Biao Han, Feng Yan, Liang Ding, Bojie Li, Liansheng Wang and Lei Zhu

Nanomaterials 2018, 8(5), 326; https://doi.org/10.3390/nano8050326 - 14 May 2018

Cited by 11 | Viewed by 4576

Abstract

We describe here the preparation of copper nanoparticles stabilized on a chitosan/poly (vinyl alcohol) composite film. This material could catalyze the borylation of α,β-unsaturated acceptors in aqueous media under mild conditions. The corresponding organoboron compounds as well as their converted β-hydroxyl products were [...] Read more.

We describe here the preparation of copper nanoparticles stabilized on a chitosan/poly (vinyl alcohol) composite film. This material could catalyze the borylation of α,β-unsaturated acceptors in aqueous media under mild conditions. The corresponding organoboron compounds as well as their converted β-hydroxyl products were all obtained in good to excellent yields. It is noteworthy that this catalyst of copper nanoparticles can be easily recycled eight times and remained catalytically reactive. This newly developed methodology provides an efficient and sustainable pathway for the synthesis of organoboron compounds and application of copper nanoparticles. Full article

(This article belongs to the Special Issue Sustainable Nanoparticles - Their Synthesis and Catalytic Applications)

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13 pages, 17243 KiB

Open AccessArticle

Iron Oxide-Cobalt Nanocatalyst for O-tert-Boc Protection and O-Arylation of Phenols

by Vilas B. Gade, Anandarup Goswami, Rajender S. Varma, Sharad N. Shelke and Manoj B. Gawande

Nanomaterials 2018, 8(4), 246; https://doi.org/10.3390/nano8040246 - 17 Apr 2018

Cited by 12 | Viewed by 4908

Abstract

Efficient and general protocols for the O-tert-boc protection and O-arylation of phenols were developed in this paper using a recyclable magnetic Fe₃O₄-Co₃O₄ nanocatalyst (Nano-Fe-Co), which is easily accessible via simple wet impregnation [...] Read more.

Efficient and general protocols for the O-tert-boc protection and O-arylation of phenols were developed in this paper using a recyclable magnetic Fe₃O₄-Co₃O₄ nanocatalyst (Nano-Fe-Co), which is easily accessible via simple wet impregnation techniques in aqueous mediums from inexpensive precursors. The results showed the catalysts were well characterized by XRD (X-ray Diffraction), ICP-AES (Inductive Coupled Plasma Atomic Emission Spectroscopy), TEM (Transmission Electron Microscopy), TOF-SIMS (Time-Of-Flight Secondary Ion Mass Spectrometry) and XPS (X-ray Photoelectron Spectroscopy). The O-tert-boc protection and O-arylation of phenols was accomplished in good to excellent yields (85–95%) and the catalyst was reusable and recyclable with no loss of catalytic activity for at least six repetitions. Full article

(This article belongs to the Special Issue Sustainable Nanoparticles - Their Synthesis and Catalytic Applications)

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14 pages, 14612 KiB

Open AccessArticle

Aqueous-Phase Hydrogenolysis of Glycerol over Re Promoted Ru Catalysts Encapuslated in Porous Silica Nanoparticles

by Kuo-Tseng Li and Ruey-Hsiang Yen

Nanomaterials 2018, 8(3), 153; https://doi.org/10.3390/nano8030153 - 9 Mar 2018

Cited by 16 | Viewed by 5549

Abstract

Activity improvement of Ru-based catalysts is needed for efficient production of valuable chemicals from glycerol hydrogenolysis. In this work, a series of Re promoted Ru catalysts encapuslated in porous silica nanoparticles (denoted as Re-Ru@SiO₂) were prepared by coating silica onto the [...] Read more.

Activity improvement of Ru-based catalysts is needed for efficient production of valuable chemicals from glycerol hydrogenolysis. In this work, a series of Re promoted Ru catalysts encapuslated in porous silica nanoparticles (denoted as Re-Ru@SiO₂) were prepared by coating silica onto the surface of chemically reduced Ru-polyvinylpyrrolidone colloids, and were used to catalyze the conversion of glycerol to diols and alcohols in water. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption, X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction (TPR) were used to characterize these nanoparticles. Effects of Ru/Si atomic ratio, Re addition, glycerol and catalyst concentrations, reaction time, temperature, and hydrogen pressure were investigated. Re addition retarded the reduction of ruthenium oxide, but increased the catalyst reactivity for glycerol hydrogenolysis. Due to its greater Ru content, Re-Ru@ SiO₂ showed much better activity (reacted at much lower temperature) and more yields of 1,2-propanediol and overall liquid-phase products than Re-Ru/SiO₂ (prepared by conventional impregnation method) reported before. The rate of glycerol disappearance exhibited first-order dependence on glycerol concentration and hydrogen pressure, with an activation energy of 107.8 kJ/mol. The rate constant increased linearly with increasing Ru/Si atomic ratio and catalyst amount. The yield of overall liquid-phase products correlated well with glycerol conversion. Full article

(This article belongs to the Special Issue Sustainable Nanoparticles - Their Synthesis and Catalytic Applications)

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13 pages, 3337 KiB

Open AccessArticle

Palladium Supported on Titanium Carbide: A Highly Efficient, Durable, and Recyclable Bifunctional Catalyst for the Transformation of 4-Chlorophenol and 4-Nitrophenol

by Guangyin Fan, Xiaojing Li, Caili Xu, Weidong Jiang, Yun Zhang, Daojiang Gao, Jian Bi and Yi Wang

Nanomaterials 2018, 8(3), 141; https://doi.org/10.3390/nano8030141 - 2 Mar 2018

Cited by 29 | Viewed by 6167

Abstract

Developing highly efficient and recyclable catalysts for the transformation of toxic organic contaminates still remains a challenge. Herein, Titanium Carbide (Ti₃C₂) MXene modified by alkali treatment process was selected as a support (designated as alk-Ti₃C₂X [...] Read more.

Developing highly efficient and recyclable catalysts for the transformation of toxic organic contaminates still remains a challenge. Herein, Titanium Carbide (Ti₃C₂) MXene modified by alkali treatment process was selected as a support (designated as alk-Ti₃C₂X₂, where X represents the surface terminations) for the synthesis of Pd/alk-Ti₃C₂X₂. Results show that the alkali treatment leads to the increase of surface area and surface oxygen-containing groups of Ti₃C₂X₂, thereby facilitating the dispersion and stabilization of Pd species on the surface of alk-Ti₃C₂X₂. The Pd/alk-Ti₃C₂X₂ catalyst shows excellent catalytic activity for the hydrodechlorination of 4-chlorophenol and the hydrogenation of 4-nitrophenol in aqueous solution at 25 °C and hydrogen balloon pressure. High initial reaction rates of 216.6 and 126.3 min⁻¹·

g_{pd}^{- 1}

are observed for the hydrodechlorination of 4-chlorophenol and hydrogenation of 4-nitrophenol, respectively. Most importantly, Pd/alk-Ti₃C₂X₂ exhibits excellent stability and recyclability in both reactions without any promoters. The superior property of Pd/alk-Ti₃C₂X₂ makes it as a potential material for practical applications. Full article

(This article belongs to the Special Issue Sustainable Nanoparticles - Their Synthesis and Catalytic Applications)

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13 pages, 12211 KiB

Open AccessCommunication

MOF-Derived Cu@Cu₂O Nanocatalyst for Oxygen Reduction Reaction and Cycloaddition Reaction

by Aram Kim, Nallal Muthuchamy, Chohye Yoon, Sang Hoon Joo and Kang Hyun Park

Nanomaterials 2018, 8(3), 138; https://doi.org/10.3390/nano8030138 - 28 Feb 2018

Cited by 74 | Viewed by 8376

Abstract

Research on the synthesis of nanomaterials using metal-organic frameworks (MOFs), which are characterized by multi-functionality and porosity, as precursors have been accomplished through various synthetic approaches. In this study, copper and copper oxide nanoparticles were fabricated within 30 min by a simple and [...] Read more.

Research on the synthesis of nanomaterials using metal-organic frameworks (MOFs), which are characterized by multi-functionality and porosity, as precursors have been accomplished through various synthetic approaches. In this study, copper and copper oxide nanoparticles were fabricated within 30 min by a simple and rapid method involving the reduction of a copper(II)-containing MOF with sodium borohydride solution at room temperature. The obtained nanoparticles consist of a copper core and a copper oxide shell exhibited catalytic activity in the oxygen reduction reaction. The as-synthesized Cu@Cu₂O core-shell nanocatalyst exhibited an enhanced limit current density as well as onset potential in the electrocatalytic oxygen reduction reaction (ORR). Moreover, the nanoparticles exhibited good catalytic activity in the Huisgen cycloaddition of various substituted azides and alkynes under mild reaction conditions. Full article

(This article belongs to the Special Issue Sustainable Nanoparticles - Their Synthesis and Catalytic Applications)

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