Thermo-responsive PNIPAM-metal hybrids: An efficient nanocatalyst for the reduction of 4-nitrophenol

Satapathy, S.; Bhol, Prachi; Chakkarambath, Aswathy; Mohanta, Jagdeep; Samantaray, Kunal; Bhat, Suresh; Panda, Subhendu K.; Mohanty, Priti S.; Si, Satyabrata

doi:10.1016/j.apsusc.2017.05.172

Cited by 59 publications

(41 citation statements)

References 53 publications

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“…Literature study also reveals the possibility of zero order kinetics of nitrophenol reduction using gold catalyst depending on the concentration of 4‐NP in excess of borohydride . The observation of first order kinetics with very high rate constant is in accordance with our earlier reports . To further ascertain whether CDs or AuNPs are responsible for reduction reaction, we performed a controlled reaction using CDs only.…”

Section: Resultssupporting

confidence: 87%

“…Reduction of 4‐NP to 4‐AP is achieved by using heterogeneous nanocatalyst and thus, designing novel materials of catalytic interest is important with respect to pollutant mitigation and resource recovery. The chemistry of catalysis depends on the surface phenomena of AuNPs . Also, silver nanoparticles are found to be as a new generation of nanocatalysts in organic transformations for efficient synthesis of fine chemicals .…”

Section: Introductionmentioning

confidence: 99%

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Carbon Dots Assisted Synthesis of Gold Nanoparticles and Their Catalytic Activity in 4‐Nitrophenol Reduction

et al. 2019

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A novel biocompatible carbon nanoparticles, i. e., carbon dots (CDs) are prepared from cheap organic precursors and are used to synthesize gold nanoparticles (AuNPs). The formation of CDs are confirmed from their absorption and emission properties. The CDs not only acts as reducing agent but also stabilizes the resulting AuNPs. The high stabilizing effect of CDs can be attributed to their hydrophilic surfaces due to the presence of ‐C=O, ‐OH, etc. functional group as confirmed from FTIR spectral analysis. Basically, two types of AuNPs are observed, one is decahedron type particles and the other one is triangular plates. The size of decahedron type AuNPs are measured to be ∼ 30 nm, whereas those of triangular plates are ∼ 100 nm. These mixture of AuNPs are used to study a model catalytic reaction, i. e., reduction of 4‐nitrophenol by NaBH4 in which the reaction is completed in 5 Mins and the reaction follows the first order kinetics with a first order rate constant of 1.28 min−1. Moreover, the resulting AuNPs can be reused for further reactions and up to 4 cycles it has been observed that the efficiency of conversion remains ∼100% with this AuNPs catalyst. Thus, functional CDs not only catalyse the formation of AuNPs, but also give them enough stability for catalytic applications in many organic transformation reactions.

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Section: Resultssupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Carbon Dots Assisted Synthesis of Gold Nanoparticles and Their Catalytic Activity in 4‐Nitrophenol Reduction

et al. 2019

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“…The nanoreactor has great application potential in the catalysis field, in particular for thermosensitive “smart nanoreactors”, which could regulate the catalytic rate by altering the temperature of catalytic systems. For instance, Satapathy et al [15] successfully synthesized a series of hybrid-nanostructured PNIPAM-Au with different shapes of AuNPs for the reduction of 4-nitrophenol (4-NP), and observed a controllable catalytic activity by altering the reaction temperature. Chen et al [16] designed a new nanoreactor structure with the spatial separation of Au and PNIPAM to use as the catalyst to reduce 4-NP, which exhibited obviously different catalytic activity at the temperature below and above the LCST of PNIPAM.…”

Section: Introductionmentioning

confidence: 99%

AuNPs-Based Thermoresponsive Nanoreactor as an Efficient Catalyst for the Reduction of 4-Nitrophenol

Liu

Zhu

et al. 2018

Nanomaterials

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A new AuNPs-based thermosensitive nanoreactor (SiO2@PMBA@Au@PNIPAM) was designed and prepared by stabilizing AuNPs in the layer of poly(N,N’-methylenebisacrylamide) (PMBA) and subsequent wrapping with the temperature-sensitive poly(N-isopropylacrylamide) (PNIPAM) layer. The new nanoreactor exhibited high dispersibility and stability in aqueous solution and effectively prevented the aggregation of AuNPs caused by the phase transformation of PNIPAM. The XPS and ATR-FTIR results indicated that AuNPs could be well stabilized by PMBA due to the electron transfer between the N atoms of amide groups in the PMBA and Au atoms of AuNPs. The catalytic activity and thermoresponsive property of the new nanoreactor were invested by the reduction of the environmental pollutant, 4-nitrophenol (4-NP), with NaBH4 as a reductant. It exhibited a higher catalytic activity at 20 °C and 30 °C (below LCST of PNIPAM), but an inhibited catalytic activity at 40 °C (above LCST of PNIPAM). The PNIPAM layer played a switching role in controlling the catalytic rate by altering the reaction temperature. In addition, this nanoreactor showed an easily recyclable property due to the existence of a silica core and also preserved a rather high catalytic efficiency after 16 times of recycling.

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“…These core-shell microgels were used to catalytically convert 4-NP to 4-aminophenol (4-AP). The authors conclude PNIPAAm-AuNPs and AuNRs have better catalytic activity, as well as recyclability compared to that of PNIPAAm-AgNPs [109]. Similarly, Shah et al [119] produced multiresponsive tercopolymer microgels (poly(NIPAAm- co -MAA- co -2-hydroxymethylmethacrylate) with homogeneously dispersed Ag and AuNPs.…”

Section: Multi-stimuli-responsive Hybrid Microgelsmentioning

confidence: 99%

“…The helix contour length is 160 μm, the dashed line indicates the wall position (Reproduced from ref. [108] Copyright 2015 John Wiley and Sons); ( d ) Transmission electron microscopy images of (A) PNIPAAm-Au nanospheres (B) PNIPAAm-AuNR and (C) PNIPAAm-Ag nanospheres [109] (Reprinted from ref. [109].…”

Section: Figurementioning

confidence: 99%

Functional Stimuli-Responsive Gels: Hydrogels and Microgels

Echeverría

Fernandes

Godinho

et al. 2018

Gels

164

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One strategy that has gained much attention in the last decades is the understanding and further mimicking of structures and behaviours found in nature, as inspiration to develop materials with additional functionalities. This review presents recent advances in stimuli-responsive gels with emphasis on functional hydrogels and microgels. The first part of the review highlights the high impact of stimuli-responsive hydrogels in materials science. From macro to micro scale, the review also collects the most recent studies on the preparation of hybrid polymeric microgels composed of a nanoparticle (able to respond to external stimuli), encapsulated or grown into a stimuli-responsive matrix (microgel). This combination gave rise to interesting multi-responsive functional microgels and paved a new path for the preparation of multi-stimuli “smart” systems. Finally, special attention is focused on a new generation of functional stimuli-responsive polymer hydrogels able to self-shape (shape-memory) and/or self-repair. This last functionality could be considered as the closing loop for smart polymeric gels.

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Thermo-responsive PNIPAM-metal hybrids: An efficient nanocatalyst for the reduction of 4-nitrophenol

Cited by 59 publications

References 53 publications

Carbon Dots Assisted Synthesis of Gold Nanoparticles and Their Catalytic Activity in 4‐Nitrophenol Reduction

Carbon Dots Assisted Synthesis of Gold Nanoparticles and Their Catalytic Activity in 4‐Nitrophenol Reduction

AuNPs-Based Thermoresponsive Nanoreactor as an Efficient Catalyst for the Reduction of 4-Nitrophenol

Functional Stimuli-Responsive Gels: Hydrogels and Microgels

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