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Rapid continuous microwave-assisted synthesis of silver nanoparticles to achieve very high productivity and full yield: from mechanistic study to optimal fabrication strategy.

Dzido G, Markowski P, Małachowska-Jutsz A, Prusik K, Jarzębski AB - J Nanopart Res (2015)

Bottom Line: Systematic studies of silver nanoparticle synthesis in a continuous-flow single-mode microwave reactor using polyol process were performed, revealing that the synthesis is exceptionally effective to give very small metal particles at full reaction yield and very high productivity.Owing to its much higher reactivity, silver acetate was shown to be far superior substrate for the synthesis of small (10-20 nm) spherical silver nanoparticles within a few seconds.The performed studies indicate an optimal strategy for the high-yield fabrication of metal particles using polyol method.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical Engineering and Process Design, Faculty of Chemistry, Silesian University of Technology, Ks. M. Strzody 7, 44-100 Gliwice, Poland.

ABSTRACT

Systematic studies of silver nanoparticle synthesis in a continuous-flow single-mode microwave reactor using polyol process were performed, revealing that the synthesis is exceptionally effective to give very small metal particles at full reaction yield and very high productivity. Inlet concentration of silver nitrate or silver acetate, applied as metal precursors, varied between 10 and 50 mM, and flow rates ranged from 0.635 to 2.5 dm(3)/h, to give 3-24 s reaction time. Owing to its much higher reactivity, silver acetate was shown to be far superior substrate for the synthesis of small (10-20 nm) spherical silver nanoparticles within a few seconds. Its restricted solubility in ethylene glycol, applied as the solvent and reducing agent, appeared to be vital for effective separation of the stage of particle growth from its nucleation to enable rapid synthesis of small particles in a highly loaded system. This was not possible to obtain using silver nitrate. All the observations could perfectly be explained by a classical LaMer-Dinegar model of NPs' formation, but taking into account also nonisothermal character of the continuous-flow process and acetate dissolution in the reaction system. The performed studies indicate an optimal strategy for the high-yield fabrication of metal particles using polyol method.

No MeSH data available.


Related in: MedlinePlus

Effect of ‘thermal history’ on size distribution histograms (by DLS) and UV–Vis spectra of silver particles synthesized using Ag-nitrate and Ag-acetate
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Related In: Results  -  Collection


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Fig4: Effect of ‘thermal history’ on size distribution histograms (by DLS) and UV–Vis spectra of silver particles synthesized using Ag-nitrate and Ag-acetate

Mentions: Experiments showed that the exit temperature of ~170 °C was a reasonable compromise for the synthesis AgNPs using Ag-nitrate, and it was ~150 °C for Ag-acetate. In perfect agreement with LMD model, the mean sizes of particles (hydrodynamic diameter detected by DLS) produced at lower exit temperatures of 149 and 90 °C, respectively for Ag-nitrate and Ag-acetate, were large, ca. 140 and 65 nm (cf. T1 and T3 in Table 1, T1 and T3 in Fig. 4), and the reactions were far from completion, despite a fairly long residence time (12 s). When the rate of substrate reduction was increased, by fixing the exit temperature at 171 °C, the size of particles obtained from Ag-nitrate decreased to 15–20 nm (T2 in Fig. 4), which could be ascribed to the increase in the rate of reduction, and hence of nucleation, resulting in a larger number of original nuclei, but the reaction yield increased only from 56 to 63 % (cf. Table 1). All these were observed for Ag-nitrate concentration of 10 mM. However, for its large (inlet) content (50 mM), which is of most practical interest, we saw a development of two-size distributions, both of them fairly narrow, with maxima at about 35 and 110 nm (T9 in Fig. 4), and the Ag0 yield achieved in 12 s was ca. 94 %. Similar bimodal size distribution patterns of AgNPs were also observed before in a low-temperature continuous-flow process (Dzido and Jarzębski 2011), and the formation of smaller particles was ascribed to the oscillation-related particles’ abrasion, more intense at higher concentrations (Zhu et al. 2004).Fig. 4


Rapid continuous microwave-assisted synthesis of silver nanoparticles to achieve very high productivity and full yield: from mechanistic study to optimal fabrication strategy.

Dzido G, Markowski P, Małachowska-Jutsz A, Prusik K, Jarzębski AB - J Nanopart Res (2015)

Effect of ‘thermal history’ on size distribution histograms (by DLS) and UV–Vis spectra of silver particles synthesized using Ag-nitrate and Ag-acetate
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4300398&req=5

Fig4: Effect of ‘thermal history’ on size distribution histograms (by DLS) and UV–Vis spectra of silver particles synthesized using Ag-nitrate and Ag-acetate
Mentions: Experiments showed that the exit temperature of ~170 °C was a reasonable compromise for the synthesis AgNPs using Ag-nitrate, and it was ~150 °C for Ag-acetate. In perfect agreement with LMD model, the mean sizes of particles (hydrodynamic diameter detected by DLS) produced at lower exit temperatures of 149 and 90 °C, respectively for Ag-nitrate and Ag-acetate, were large, ca. 140 and 65 nm (cf. T1 and T3 in Table 1, T1 and T3 in Fig. 4), and the reactions were far from completion, despite a fairly long residence time (12 s). When the rate of substrate reduction was increased, by fixing the exit temperature at 171 °C, the size of particles obtained from Ag-nitrate decreased to 15–20 nm (T2 in Fig. 4), which could be ascribed to the increase in the rate of reduction, and hence of nucleation, resulting in a larger number of original nuclei, but the reaction yield increased only from 56 to 63 % (cf. Table 1). All these were observed for Ag-nitrate concentration of 10 mM. However, for its large (inlet) content (50 mM), which is of most practical interest, we saw a development of two-size distributions, both of them fairly narrow, with maxima at about 35 and 110 nm (T9 in Fig. 4), and the Ag0 yield achieved in 12 s was ca. 94 %. Similar bimodal size distribution patterns of AgNPs were also observed before in a low-temperature continuous-flow process (Dzido and Jarzębski 2011), and the formation of smaller particles was ascribed to the oscillation-related particles’ abrasion, more intense at higher concentrations (Zhu et al. 2004).Fig. 4

Bottom Line: Systematic studies of silver nanoparticle synthesis in a continuous-flow single-mode microwave reactor using polyol process were performed, revealing that the synthesis is exceptionally effective to give very small metal particles at full reaction yield and very high productivity.Owing to its much higher reactivity, silver acetate was shown to be far superior substrate for the synthesis of small (10-20 nm) spherical silver nanoparticles within a few seconds.The performed studies indicate an optimal strategy for the high-yield fabrication of metal particles using polyol method.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical Engineering and Process Design, Faculty of Chemistry, Silesian University of Technology, Ks. M. Strzody 7, 44-100 Gliwice, Poland.

ABSTRACT

Systematic studies of silver nanoparticle synthesis in a continuous-flow single-mode microwave reactor using polyol process were performed, revealing that the synthesis is exceptionally effective to give very small metal particles at full reaction yield and very high productivity. Inlet concentration of silver nitrate or silver acetate, applied as metal precursors, varied between 10 and 50 mM, and flow rates ranged from 0.635 to 2.5 dm(3)/h, to give 3-24 s reaction time. Owing to its much higher reactivity, silver acetate was shown to be far superior substrate for the synthesis of small (10-20 nm) spherical silver nanoparticles within a few seconds. Its restricted solubility in ethylene glycol, applied as the solvent and reducing agent, appeared to be vital for effective separation of the stage of particle growth from its nucleation to enable rapid synthesis of small particles in a highly loaded system. This was not possible to obtain using silver nitrate. All the observations could perfectly be explained by a classical LaMer-Dinegar model of NPs' formation, but taking into account also nonisothermal character of the continuous-flow process and acetate dissolution in the reaction system. The performed studies indicate an optimal strategy for the high-yield fabrication of metal particles using polyol method.

No MeSH data available.


Related in: MedlinePlus