Novel synthesis of Ag@Co/RGO nanocomposite and its high catalytic activity towards hydrogenation of 4-nitrophenol to 4-aminophenol

Krishna, Rahul; Fernandes, Diana M.; Dias, Catarina; Ventura, J.; Ramana, E. Venkata; Freire, Cristina; Titus, Elby

doi:10.1016/j.ijhydene.2014.12.045

Cited by 62 publications

(36 citation statements)

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“…The progress of the reaction was monitored by the UV–visible technique. In order to detect the whole catalytic reduction process clearly, the concentrations of NaBH 4 and catalyst were only 50% and 2% of the corresponding values reported in the literature . For comparison, a blank test was conducted with a mixture of 4‐NP, NaBH 4 and RGO/CS colloid without AgNPs, and the result shows that neither the decrease in absorbance of –NO 2 at 400 nm nor the change of the solution color were observed, indicating that the catalytic reduction of –NO 2 will not occur if Ag/RGO/CS is not used as catalyst in the 4‐NP reduction system.…”

Section: Resultsmentioning

confidence: 99%

Facile preparation of silver/reduced graphene oxide/chitosan colloid and application of the nanocomposite in antibacterial and catalytic activity

Guo

Yin

et al. 2018

Polymer International

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Reduced graphene oxide (RGO) decorated with silver nanoparticles (AgNPs) was synthesized by a facile solution‐based approach in chitosan (CS) solution. The morphology and elemental composition of as‐prepared Ag/RGO/CS colloid were characterized by SEM and energy dispersive X‐ray spectroscopy, respectively. TEM images show that most of the AgNPs are uniformly dispersed in the CS matrix while the other nanoparticles are decorated on the RGO nanosheets. XRD indicates that the interlayer distance of RGO is between 0.34 and 1.87 nm while the diameter of face‐centered cubic AgNPs is no more than 30 nm. Fourier transform infrared spectroscopy of the Ag/RGO/CS colloid confirms the formation of AgNPs and RGO. X‐ray photoelectron spectroscopy proves that both the Ag − O bond and the C − N bond exist in the nanocomposite. Antimicrobial assays were performed using the most common species of Gram bacteria. The inhibitory effect indicates that the incorporation of AgNPs and RGO significantly improves the antimicrobial activity of CS colloid. In addition, the nanocomposite colloid exhibits significant catalytic activity toward the reduction of 4‐nitrophenol by NaBH4. © 2018 Society of Chemical Industry

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Section: Resultsmentioning

confidence: 99%

Facile preparation of silver/reduced graphene oxide/chitosan colloid and application of the nanocomposite in antibacterial and catalytic activity

Guo

Yin

et al. 2018

Polymer International

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“…The short hydrogen bond distance O ---H-O-H (1.631 Å) in the PdO/H2O complex, along with a significant negative chargetransfer from PdO to H2O (-0.085 e), points to a form of palladium oxide strongly bound to water. Finally, we have evaluated the catalytic activity of our PdO nanoparticles by monitoring the reduction of p-nitrophenol (PNP) in borohydride solution, which is only possible in the presence of an appropriate catalyst [46] and represents a classical test for its efficiency [47][48][49][50][51]. By adding NaBH 4 , the aqueous solution of PNP becomes alkaline and the absorption band of p-nitrophenolate occurs at 400 nm in the absorption spectrum, which does not appreciably decrease in time.…”

Section: Scheme 1 Proposed Mechanism Of Formation Of Palladium Oxidementioning

confidence: 99%

Palladium Oxide Nanoparticles: Preparation, Characterization and Catalytic Activity Evaluation

et al. 2020

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Stable palladium oxide nanoparticles were prepared in aqueous suspension with a very simple procedure, by dissolving palladium nitrate in water at a concentration around 10−4 M. UV-visible absorption spectroscopy was adopted to follow the formation of these nanoparticles, which were characterized by TEM microscopy, along with XRD, XPS and Raman measurements. DFT calculations allowed to interpret the Raman data and to clarify the species present at the surface of the nanoparticles. The catalytic activity of the latter was evaluated by monitoring the reduction of p-nitrophenol to p-aminophenol. This investigation paves the way to the use of these colloidal nanoparticles in processes of heterogeneous catalysis, in particular those concerning the catalytic degradation of aromatic derivatives that represent a serious danger for the environment as pollutants, as in the case of p-nitrophenol.

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“…The other one, known as the charge redistribution effect, is due to electronic effects, which can facilitate the hydrogenation of the nitro-group [36], an explanation for AuPd bimetallic systems can be found in references [40,41]. Krisnha and coworkers attributed the enhancement of the catalytic performance of the bimetallic system CuNi [37] or AgCo [42] on the basis of synergetic effect via spill-over mechanism. In our work, we have shown that a small loading addition of Pd (1 %wt) to Cu (5%) greatly reduces the nanoparticle size from 7.1 to 2.7 nm, generating more active sites (higher dispersion).…”

Section: Catalytic Testsmentioning

confidence: 99%

CuPd Bimetallic Nanoparticles Supported on Magnesium Oxide as an Active and Stable Catalyst for the Reduction of 4-Nitrophenol to 4-Aminophenol

Morales¹

2018

Int. J. Green Technol.

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Abstract:In this work, we report the synthesis and characterization of a catalyst based on bimetallic CuPd nanostructures generated over a magnesium oxide support. Its catalytic activity and reusability have been tested in the reduction of 4-nitrophenol as a model reaction using NaBH4 as the source of hydrogen for the reduction of the nitro-group. The structure, composition and morphology of the catalysts were studied by N2 physisorption, X-ray diffraction (XRD), Transmission Electron Microscopy (TEM) and X-ray Photoelectron Spectroscopy (XPS). The reaction kinetics of reduction of 4-nitrophenol to 4-aminophenol has been followed by UV-visible spectrophotometry, and its apparent rate constant has been determined and compared with its monometallic counterparts. All the tested catalysts exhibited remarkable high activity and excellent stability upon reuse for multiple consecutive cycles. We found out that a small loading addition of Pd to Cu catalyst greatly improved the catalytic activity in comparison with the monometallic samples. Our characterization results pointed out a higher metallic dispersion degree as the main explanation for this enhanced performance. CuPd/MgO is highly competitive or outperforms the catalytic activity of other bimetallic systems reported in literature.

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Novel synthesis of Ag@Co/RGO nanocomposite and its high catalytic activity towards hydrogenation of 4-nitrophenol to 4-aminophenol

Cited by 62 publications

References 50 publications

Facile preparation of silver/reduced graphene oxide/chitosan colloid and application of the nanocomposite in antibacterial and catalytic activity

Facile preparation of silver/reduced graphene oxide/chitosan colloid and application of the nanocomposite in antibacterial and catalytic activity

Palladium Oxide Nanoparticles: Preparation, Characterization and Catalytic Activity Evaluation

CuPd Bimetallic Nanoparticles Supported on Magnesium Oxide as an Active and Stable Catalyst for the Reduction of 4-Nitrophenol to 4-Aminophenol

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