Bimetallic Pt?Ni nanoparticles can catalyze reduction of aromatic nitro compounds by sodium borohydride in aqueous solution

Ghosh, Sujit Kumar; Mandal, Manas K.; Kundu, Subrata; Nath, Sankar Kumar; Pal, Tarasankar

doi:10.1016/j.apcata.2004.03.017

Cited by 465 publications

(130 citation statements)

References 29 publications

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“…In comparison to the results found in the literature, the apparent activation energy E A for the reaction catalyzed via the Pt NPs is rather high with E A = 99 ± 23 kJ•mol −1 compared to the values between 30 and 45 kJ•mol −1 , which are typical for platinum and platinum-based nanoparticles catalyzed reactions [27,28,31]. This high apparent activation energy could be explained by desorption of the NaBH 4 from the catalyst surface at high temperatures.…”

Section: Methodsmentioning

confidence: 54%

“…The reduction of 4-nitrophenol via NaBH 4 can be catalyzed not only by monometallic Pt nanoparticles, but also by the bimetallic PtBi and PtPb nanoparticles. However, the reduction via the three different catalysts does not follow pseudo first-order kinetics, even with a 200-times excess of the reducing agent, which is the common approach in the literature [28,29,[31][32][33]. Our results strongly indicate: (1) the presence of first-order kinetics only for the first step of the reduction mechanism, i.e., the hydrogenation of 4-nitrophenol to 4-nitrosophenol; and (2) a strong influence of the temperature on the kinetics of the reaction, which cannot be described with the Arrhenius equation.…”

Section: Discussionmentioning

confidence: 99%

“…As reported in [27], the reaction follows the Langmuir-Hinshelwood mechanism. However, if a large enough amount of NaBH 4 is used (at least >100-times more than 4-nitrophenol), the kinetics simplify to a pseudo first-order reaction [28][29][30][31][32]. Thus, to test the catalytic activity of the synthesized nanoparticles, we used an excess of NaBH 4 and treated the reaction as a pseudo first-order reaction.…”

Section: Methodsmentioning

confidence: 99%

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Catalytic Activity of Mono- and Bi-Metallic Nanoparticles Synthesized via Microemulsions

et al. 2014

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Water-in-oil (w/o) microemulsions were used as a template for the synthesis of mono-and bi-metallic nanoparticles. For that purpose, w/o-microemulsions containing H 2 PtCl 6 , H 2 PtCl 6 + Pb(NO 3 ) 2 and H 2 PtCl 6 + Bi(NO) 3 , respectively, were mixed with a w/o-microemulsion containing the reducing agent, NaBH 4 . The results revealed that it is possible to synthesize Pt, PtPb and PtBi nanoparticles of ~3-8 nm in diameter at temperatures of about 30°C. The catalytic properties of the bimetallic PtBi and PtPb nanoparticles were studied and compared with monometallic platinum nanoparticles. Firstly, the electrochemical oxidation of formic acid to carbon monoxide was investigated, and it was found that the resistance of the PtBi and PtPb nanoparticles against the catalyst-poisoning carbon monoxide was significantly higher compared to the Pt nanoparticles. Secondly, investigating the reduction of 4-nitrophenol to 4-aminophenol,we found that the bimetallic NPs are most active at 23 °C, while the order of the activity changes at higher temperatures, i.e., that the Pt nanoparticles are the most active ones at 36 and 49 °C. Furthermore, we observed a strong influence of the support, which was either a polymer or Al 2 O 3 . Thirdly, for the hydrogenation of allylbenzene to propylbenzene, the monometallic Pt NPs turned out to be the most active catalysts, followed by the PtPb and PtBi NPs. Comparing the two bimetallic nanoparticles, one sees that the PtPb NPs are significantly more active than the respective PtBi NPs. OPEN ACCESSCatalysts 2014, 4 257

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Section: Methodsmentioning

confidence: 54%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Catalytic Activity of Mono- and Bi-Metallic Nanoparticles Synthesized via Microemulsions

et al. 2014

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“…The spectra exhibited isobestic points at ~280nm, ~240 nm, and ~220 nm. The presence of these isobestic points in the UV-vis spectra indicated that 4-aminophenol (4-AP) is the only aromatic byproduct formed, as concluded by several studies [11][12][13]37]. The principal absorbance wavelengths of 4-NL and 4-AP are 400 nm and 293 nm, respectively.…”

Section: Activity Of Pd-on-au Nps For 4-nitrophenol Reductionmentioning

confidence: 81%

Improving gold catalysis of nitroarene reduction with surface Pd

et al. 2016

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Nitroarene reduction reactions are commercialized catalytic processes that play a key role in the synthesis of many products including medicines, rubbers, dyes, and herbicides. Whereas bimetallic compositions have been studied, a better understanding of the bimetallic structure effects may lead to improved industrial catalysts. In this work, the influence of surface palladium atoms supported on 3-nm Au nanoparticles (Pd-on-Au NPs) on catalytic activity for 4-nitrophenol reduction is explored. Batch reactor studies indicate Pd-on-Au NPs exhibit maximum catalytic activity at a Pd surface coverage of 150 sc%, with an initial turnover frequency of ~3.7 mol-nitrophenol/mol-metal surface /s, which was ~5.5× and ~13× more active than pure Au NPs and Pd NPs, respectively. Pd NPs, Au NPs, and Pd-on-Au NPs below 175 sc% show compensation behavior. Three-dimensional Pd surface ensembles (with ~4-5 atoms) previously identified through x-ray adsorption spectroscopy provide the active sites responsible for the catalytic maximum. These results demonstrate the ability to adjust systematically a structural feature (i.e., Pd surface coverage) to yield a more active material.

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“…Since this reaction was first reported in 2002 by T. Pal et al [4] and K. Esumi et al [5], a huge number of research groups have used it in order to evaluate the catalytic properties (kinetics, stability) in the aqueous phase of lab-synthetized metal nanoparticles [6]. Although more cost-effective metal such as copper has drawn high attention in recent years [7], as we exposed in a former work [8], the noble and costly metal catalysts such as gold [9,10], Pt [11] or Ag [12], have been the focus of most of the reported literature. Apart from these precious metals, catalysts based on Pd have been reported to exhibit excellent catalytic performance in this reaction in terms of activity, stability and reusability [13].…”

Section: Introductionmentioning

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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Bimetallic Pt?Ni nanoparticles can catalyze reduction of aromatic nitro compounds by sodium borohydride in aqueous solution

Cited by 465 publications

References 29 publications

Catalytic Activity of Mono- and Bi-Metallic Nanoparticles Synthesized via Microemulsions

Catalytic Activity of Mono- and Bi-Metallic Nanoparticles Synthesized via Microemulsions

Improving gold catalysis of nitroarene reduction with surface Pd

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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