Platinum nanoparticles generated in spherical polyelectrolyte brushes and their high catalytic activity

Wu, Shuang; Zhu, Zhongming; Siepenkötter, Till; Guo, Xuhong

doi:10.1002/apj.655

Cited by 8 publications

(4 citation statements)

References 29 publications

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“…[88][89][90] Some time ago we demonstrated that spherical polyelectrolyte brushes (SPB) 29,30 are highly suitable carrier system for the immobilization of various metal nanoparticles. 13,14,38,[91][92][93][94][95][96] The SPB particles consist of a polystyrene core onto which a dense layer of polyelectrolyte brushes is grafted. The metal ions are immobilized in the brush layer as counter-ions.…”

Section: Carriers and Nanoreactors: A Surveymentioning

confidence: 99%

Catalysis by Metallic Nanoparticles in Solution: Thermosensitive Microgels as Nanoreactors

Roa

Angioletti‐Uberti

Lü

et al. 2018

Zeitschrift Für Physikalische Chemie

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Metallic nanoparticles have been used as catalysts for various reactions, and the huge literature on the subject is hard to overlook. In many applications, the nanoparticles must be affixed to a colloidal carrier for easy handling during catalysis. These "passive carriers" (e.g., dendrimers) serve for a controlled synthesis of the nanoparticles and prevent coagulation during catalysis.Recently, hybrids from nanoparticles and polymers have been developed that allow us to change the catalytic activity of the nanoparticles by external triggers. In particular, single nanoparticles embedded in a thermosensitive network made from poly(N-isopropylacrylamide) (PNIPAM) have become the most-studied examples of such hybrids: Immersed in cold water, the PNIPAM network is hydrophilic and fully swollen. In this state, hydrophilic substrates can diffuse easily through the network, and react at the surface of the nanoparticles. Above the volume transition located at 32°C, the network becomes hydrophobic and shrinks. Now hydrophobic substrates will preferably diffuse through the network and react with other substrates in the reaction catalyzed by the enclosed nanoparticle. Such "active carriers", may thus be viewed as true nanoreactors that open new ways for the use of nanoparticles in catalysis. 3In this review, we give a survey on recent work done on these hybrids and their application in catalysis. The aim of this review is threefold: We first review hybrid systems composed of nanoparticles and thermosensitive networks and compare these "active carriers" to other colloidal and polymeric carriers (e.g., dendrimers). In a second step we discuss the model reactions used to obtain precise kinetic data on the catalytic activity of nanoparticles in various carriers and environments. These kinetic data allow us to present a fully quantitative comparison of different nanoreactors. In a final section we shall present the salient points of recent efforts in the theoretical modeling of these nanoreactors. By accounting for the presence of a free-energy landscape for the reactants' diffusive approach towards the catalytic nanoparticle, arising from solvent-reactant and polymeric shell-reactant interactions, these models are capable of explaining the emergence of all the important features observed so far in studies of nanoreactors. The present survey also suggests that such models may be used for the design of future carrier systems adapted to a given reaction and solvent. 4

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Section: Carriers and Nanoreactors: A Surveymentioning

confidence: 99%

Catalysis by Metallic Nanoparticles in Solution: Thermosensitive Microgels as Nanoreactors

Roa

Angioletti‐Uberti

Lü

et al. 2018

Zeitschrift Für Physikalische Chemie

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“…Among multiple techniques, phase separation by polyelectrolytes was reported to be able to achieve selective protein adsorption. − When a polyelectrolyte is modified on a core, a spherical polyelectrolyte brush is formed, which could be an ideal carrier for selective protein adsorption as a mobile stationary phase in a solution. This is different from ion-exchange chromatography by which high resolution of proteins can be obtained.…”

Section: Introductionmentioning

confidence: 99%

Selective Protein Separation Based on Charge Anisotropy by Spherical Polyelectrolyte Brushes

et al. 2020

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Protein purification is of vital importance in the food industry, drug discovery, and other related fields. Among many separation methods, polyelectrolyte (PE)-based phase separation was developed and recognized as a low-cost purification technique. In this work, spherical polyelectrolyte brushes (SPBs) with a high specific surface area were utilized to study the protein accessibility and selective protein binding on highly charged nanoparticles (NPs) as well as the selective phase separation of proteins. The correlation between charge anisotropy, protein binding, and phase separation was investigated on various protein systems including those proteins with similar isoelectric points (pI) such as bovine serum albumin (BSA) and β-lactoglobulin (BLG), proteins with similar molecular weights such as BSA and hemoglobin (HB), and even protein variants (BLG-A and -B) with a tiny difference of amino acids. The nonspecific electrostatic interaction studied by turbidimetric titrations and isothermal calorimetry titration (ITC) indicates a specific binding between proteins and SPBs arising from the charge anisotropy of proteins. An optimized output based on selective protein binding on SPBs could be correlated for efficient protein separation through tuning external conditions including pH and ionic strength. These findings, therefore, proved that phase separation based on selective protein adsorption by SPBs was an efficient alternative for protein separation compared with the traditional practice.

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“…The reason was that the reducibility of NaBH 4 was quite strong and it could directly turn TeO 3 2− into Te 2− while N 2 H 4 only could reduce TeO 3 2− to Te under the same condition [15]. And if firstly adding N 2 H 4 , the rapid nucleation of QDs, a crucial factor of highly luminescent QD generation, could be seriously prevented due to the decreasing reaction rate of NaBH 4 at high pH values [16,17]. Because the N 2 H 4 , the strong base, would increase the pH of solution to 13 at which the reaction rate of the next addition of NaBH 4 could slow down and the PL of QDs largely decreased [18].…”

Section: Resultsmentioning

confidence: 99%

Simple synthesis of high-quality CdTe QDs in spherical polyelectrolyte brushes with stable and reversible photoluminescence

et al. 2015

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A facile method of high-quality CdTe quantum dots (QDs) synthesis in spherical polyelectrolyte brushes (SPBs) was reported in this work. The size of CdTe QDs, with emission color from green to red, could be tuned by adjusting the duration of nucleation, feed ratio of reductants (NaBH 4 / N 2 H 4 ), and pH of precursor (SPB solution). Short duration of nucleation and low ratio of NaBH 4 /N 2 H 4 could promote the growth rate of QDs to form big-sized CdTe QDs. The pH of SPB solution, in the range of 7-9, was optimal condition for formation of high-quality QDs. The SPB@CdTe exhibited high photochemical stability as the pH of mixture was above 10, which could be stored in the visible light for several months without aggregation and optical deterioration. The photoluminescence emission of SPB@CdTe could be reversibly quenched and restored with shrinkage and swollen shell if employed pH as a regulator.

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Platinum nanoparticles generated in spherical polyelectrolyte brushes and their high catalytic activity

Cited by 8 publications

References 29 publications

Catalysis by Metallic Nanoparticles in Solution: Thermosensitive Microgels as Nanoreactors

Catalysis by Metallic Nanoparticles in Solution: Thermosensitive Microgels as Nanoreactors

Selective Protein Separation Based on Charge Anisotropy by Spherical Polyelectrolyte Brushes

Simple synthesis of high-quality CdTe QDs in spherical polyelectrolyte brushes with stable and reversible photoluminescence

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