Effect of crosslinker feed content on catalaytic activity of silver nanoparticles fabricated in multiresponsive microgels

Farooqi, Zahoor H.; Khan, Shanza Rauf; Hussain, Tajamal; Begum, Robina; Ejaz, Kiran; Majeed, Shumaila; Ajmal, Muhammad; Kanwal, Farah

doi:10.1007/s11814-014-0117-0

Cited by 60 publications

(29 citation statements)

References 77 publications

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“…AAc is an acidic monomer that ionizes when the pH of the medium is greater than its pK a value ( ∼ 4.25). 45 First of all, the pH of the solution was increased above 4.25 using a base like sodium hydroxide, so that carboxyl groups (-COOH) are ionized and converted into negatively charged carboxylate ions (-COO − ). Then AgNO 3 is added to the reaction mixture.…”

Section: Growth Of Silver Nanoparticles Within P(nipam-co-aac) Microgelsmentioning

confidence: 99%

Effect of acrylic acid feed contents of microgels on catalytic activity of silver nanoparticles fabricated hybrid microgels

Farooqi¹,

Khan²,

Begum³

et al. 2015

Turk J Chem

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Abstract:We synthesized poly(N-isopropylacrylamide-co-acrylic acid) microgels with 1, 3, 5, and 7 mol percentage of acrylic acid. Silver nanoparticles were fabricated inside these microgels at room temperature. Pure microgels were characterized by Fourier transform infrared (FTIR) spectroscopy and dynamic light scattering (DLS). Hybrid microgels were characterized by UV-Visible spectroscopy. The size of the silver nanoparticles increased with an increase in the content of acrylic acid. Catalytic activity of these hybrid microgels was investigated using UV-Visible spectrophotometry.Induction time decreased from 8.8 to 2.6 min and the value of apparent rate constant decreased from 0.226 to 0.109 min −1 , when the content of acrylic acid was increased from 1 to 7 mol %. This decrease in induction time was due to decrease in the surface area of nanoparticles present within the microgels with an increase in the feed contents of acrylic acid. The decrease in the value of apparent rate constant was due to an increase in the size of nanoparticles fabricated within the microgels with an increase in mol percentage of acrylic acid. The linear relation between apparent rate constant and feed contents of acrylic acid can be used for quantitative analysis of contents of acrylic acid present in polymer microgels.

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Section: Growth Of Silver Nanoparticles Within P(nipam-co-aac) Microgelsmentioning

confidence: 99%

Effect of acrylic acid feed contents of microgels on catalytic activity of silver nanoparticles fabricated hybrid microgels

Farooqi¹,

Khan²,

Begum³

et al. 2015

Turk J Chem

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“…18 We have also investigated the effect of the mole percentage of crosslinker on the size of nanoparticles and catalytic activity of Ag-p(NIPAM-co-AAc) hybrid microgels. 10 We recently published the effect of mole percentage of ionic monomer on size of nanoparticles and catalytic activity of Ag-p(NIPAM-co-AAc) hybrid microgels. 17 In continuation of this work, herein we report a new microgel system containing NIPAM and AAAc fabricated with Ag nanoparticles for catalytic reduction of different nitroarenes in aqueous medium.…”

Section: Aam)]mentioning

confidence: 99%

Fabrication of silver nanoparticles in poly (N-isopropylacrylamide-co-allylacetic acid) microgels for catalytic reduction of nitroarenes

Farooqi¹,

Tariq²,

Begum³

et al. 2015

Turk J Chem

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Poly(N-isopropylacrylamide-co-allyl acetic acid) [p(NIPAM-co-AAAc)] microgels were synthesized in aqueous medium by free radical emulsion polymerization using N-isopropylacrylamide as monomer, allylacetic acid as comonomer, and N,N-methylene-bis-acrylamide as cross-linker. Silver nanoparticles were fabricated inside the microgels by in situ reduction of silver ions. Microgels were analyzed by UV-visible spectroscopy, FTIR, XRD, TEM, and DLS. The formation of silver nanoparticles was confirmed by UV-visible spectroscopy. UV-visible spectra of the Ag-poly(Nisopropylacrylamide-co-allyl acetic acid) hybrid microgels showed a prominent absorption peak at about 411 nm. This peak was due to the surface plasmon resonance effect of silver nanoparticles. The hybrid microgels were used as catalyst for the reduction of nitroarenes. The reduction reactions were found to be first order with respect to nitroarenes with the values of apparent rate constant (k app) equal to 0.248, 0.215, and 0.089 min −1 for 4-nitrophenol, 4-nitroaniline, and nitrobenzene respectively at 27 • C in aqueous medium. Silver nanoparticles were found to be a more effective and efficient catalyst for reduction of 4-nitrophenol and 4-nitroaniline as compared to nitrobenzene.

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“…Microgel particles are commonly used as microreactors for fabrication of Ag NPs due to the presence of specific functionalities inside the network [9,[20][21][22]. The crosslinking and presence of some special functional groups like COOH in microgels protects Ag NPs from coagulation [19,23], to maintain their surface characteristics along with high catalytic activity as compared to other supporting materials [24,25]. Microgels containing Ag NPs respond to different environmental triggers, like pH [26] and temperature [19].…”

Section: Introductionmentioning

confidence: 99%

Engineering of silver nanoparticle fabricated poly (N-isopropylacrylamide-co-acrylic acid) microgels for rapid catalytic reduction of nitrobenzene

Farooqi

Naseem

Ijaz

et al. 2015

Journal of Polymer Engineering

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Abstract Three different poly(N-isopropylacrylamide-co-acrylic acid) [p(NIPAM-AA)] microgel samples were prepared using a precipitation polymerization method by varying the concentration of NIPAM and AA in aqueous medium. The microgels were used as microreactors to fabricate Ag nanoparticles (NPs) by in situ a reduction method. Fourier transform infrared (FTIR) and UV-visible spectroscopy were used to characterize the pure and hybrid microgels. The hybrid microgels with different AA content were used as catalysts for reduction of nitrobenzene (NB) into aniline. The progress of the reaction was monitored by a UV-visible spectrophotometer. The results show that the value of the apparent rate constant for catalytic reduction of NB decreases from 0.431 min-1 to 0.227 min-1 by increasing AA content from 3 mol% to 7 mol%, respectively. Decrease in apparent rate constant with increase of AA content can be attributed to an increase in hydrophilicity with increase of AA contents of the microgels. The increase in induction period with increase of AA contents indicates that diffusion of NB towards the catalytic surface becomes difficult due to an increase of hydrophilicity.

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Effect of crosslinker feed content on catalaytic activity of silver nanoparticles fabricated in multiresponsive microgels

Cited by 60 publications

References 77 publications

Effect of acrylic acid feed contents of microgels on catalytic activity of silver nanoparticles fabricated hybrid microgels

Effect of acrylic acid feed contents of microgels on catalytic activity of silver nanoparticles fabricated hybrid microgels

Fabrication of silver nanoparticles in poly (N-isopropylacrylamide-co-allylacetic acid) microgels for catalytic reduction of nitroarenes

Engineering of silver nanoparticle fabricated poly (N-isopropylacrylamide-co-acrylic acid) microgels for rapid catalytic reduction of nitrobenzene

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