scholarly journals Anion Dependent Particle Size Control of Platinum Nanoparticles Synthesized in Ethylene Glycol

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2092
Author(s):  
Johanna Schröder ◽  
Sarah Neumann ◽  
Jonathan Quinson ◽  
Matthias Arenz ◽  
Sebastian Kunz
Keyword(s):  
Particle Size ◽  
Ethylene Glycol ◽  
Platinum Nanoparticles ◽  
Metal Salt ◽  
Size Control ◽  
Thermal Reduction ◽  
Polyol Synthesis ◽  
Molar Ratio ◽  
Established Method ◽  
Anion Effect

The polyol synthesis is a well-established method to form so-called “surfactant-free” nanoparticles (NPs). In the present study, the NP size resulting from the thermal reduction of the precursors H2PtCl6, H2Pt(OH)6, or Pt(acac)2 in presence of the bases NaOH or Na(acac) at different concentrations is studied. It is shown that the size control depends more strongly on the nature of the precursor (metal salt) than on the anion present in the base. The latter is surprising as the concentration of the base anion is often an important factor to achieve a size control. The reduction of H2PtCl6 or H2Pt(OH)6 in presence of NaOH and Na(acac) confirm the observation that the NP size is determined by the OH−/Pt molar ratio and expands it to the base anion/Pt molar ratio. In contrast, the reduction of Pt(acac)2 in presence of the bases NaOH (previous reports) or Na(acac) (shown in the present work) leads to larger NPs of ca. 3 nm, independent of the concentration of the base anions. Hence, the anion effect observed here seems to originate predominantly from the nature of the precursor (precursor anion dependence) and only for certain precursors as H2PtCl6 or H2Pt(OH)6 the size control depends on the base anion/Pt molar ratio.

scholarly journals Anion Dependent Particle Size Control of Platinum Nanoparticles Synthesized in Ethylene Glycol

2021 ◽  
Author(s):  
Johanna Schröder ◽  
Sarah Neumann ◽  
Jonathan Quinson ◽  
Matthias Arenz ◽  
Sebastian Kunz
Keyword(s):  
Particle Size ◽  
Ethylene Glycol ◽  
Platinum Nanoparticles ◽  
Size Control ◽  
Particle Size Control

scholarly journals Anion Dependent Particle Size Control of Platinum Nanoparticles Synthesized in Ethylene Glycol

2021 ◽  
Author(s):  
Johanna Schröder ◽  
Sarah Neumann ◽  
Jonathan Quinson ◽  
Matthias Arenz ◽  
Sebastian Kunz
Keyword(s):  
Particle Size ◽  
Ethylene Glycol ◽  
Platinum Nanoparticles ◽  
Size Control ◽  
Particle Size Control

Microwave-assisted polyol synthesis of Ag powders

2003 ◽  
Vol 18 (4) ◽  
pp. 747-750 ◽  
Author(s):  
Hiroaki Katsuki ◽  
Sridhar Komarneni
Keyword(s):  
Particle Size ◽  
Ethylene Glycol ◽  
Polyol Synthesis ◽  
Metal Powders ◽  
Silver Particles ◽  
Microwave Assisted ◽  
Silver Metal

Silver metal powders were prepared through reduction of AgNO3 in ethylene glycol using microwave-polyol (M-P) and conventional-polyol (C-P) reactions at 100–200 °C. Powders of Ag were rapidly produced by microwave-assisted reaction at temperatures above 160 °C. The formation yield of Ag powders from AgNO3 reached 97.8% after treatment for 135 min at 140 °C and 98.6% after treatment for 23 min at 160 °C. Compared to the formation of Ag powders using a C-P reaction, a M-P reaction led to increased rate of formation by 6.5 times at 160 °C, 5.2 times at 140 °C, and 3 times at 130 °C. Silver particles of 0.3–2 μm in diameter were produced using M-P and C-P reactions at 100–120 °C. The particle size of Ag powders increased with increasing reaction temperatures and times, and particles strongly aggregated at 160 °C using C-P and M-P reactions.

scholarly journals Particle Size-Controlled Growth of Carbon-Supported Platinum Nanoparticles (Pt/C) through Water-Assisted Polyol Synthesis

ACS Omega ◽  
2019 ◽  
Vol 4 (13) ◽  
pp. 15711-15720 ◽  
Author(s):  
Raghunandan Sharma ◽  
Yue Wang ◽  
Fan Li ◽  
Jessica Chamier ◽  
Shuang Ma Andersen
Keyword(s):  
Particle Size ◽  
Platinum Nanoparticles ◽  
Polyol Synthesis ◽  
Controlled Growth ◽  
Supported Platinum ◽  
Size Controlled

Optimizing Preparation Technological Parameters of Nano-LiAlO2 Powder by Orthogonal Experiment

2011 ◽  
Vol 415-417 ◽  
pp. 602-605
Author(s):  
Sheng Cui ◽  
Ben Lan Lin ◽  
Zhi Qiang Gao ◽  
Xiao Dong Shen
Keyword(s):  
Particle Size ◽  
Phase Composition ◽  
Citric Acid ◽  
Metal Salt ◽  
Orthogonal Experiment ◽  
Minimum Size ◽  
Molar Ratio ◽  
Sintering Process ◽  
Technological Parameters

Citrate hydrolyzing method was used to prepare nano-LiAlO2 powder, and the technological parameters were optimized by orthogonal experiment. The minimum size of LiAlO2 powder was about 100nm, obtained when the green performs were sintered at 690°C for 2h, with the molar ratio of citric acid and metal-salt of 1:1 and concentration of Li+ of 0.5mol/L. XRD and SEM were used to examine the phase composition, particle size and microstructure. The LiAlO2 powder had been agglomerated during the sintering process.

Transesterification of NDC with EG: Effects of Reaction Conditions on NDC Conversion

2013 ◽  
Vol 807-809 ◽  
pp. 2774-2778
Author(s):  
Lin Ping Sun ◽  
Qian Qiao
Keyword(s):  
Reaction Time ◽  
Ethylene Glycol ◽  
Reaction Temperature ◽  
Zinc Acetate ◽  
Metal Salt ◽  
Metal Salts ◽  
Molar Ratio ◽  
Temperature Reaction ◽  
Reaction Conditions ◽  
Optimum Reaction

Transesterification of dimethyl 2,6-napthalene dicarboxylate with ethylene glycol over metal salts catalyst was empolyed as probe reation. The effects of reaction temperature, reaction time, the molar ratio of ethylene glycol to dimethyl 2,6-napthalene dicarboxylate, N2 flowrate, kind of metal salt on the conversion of dimethyl 2,6-napthalene dicarboxylate have been investigated. The results showed that the sequence of influence was as follows: reaction temperature > reaction time > ethylene glycol/dimethyl 2,6-napthalene dicarboxylate molar ratio > amount of the catalyst. The optimum reaction conditions were 210 oC of reaction temperature, 240 min of reaction time, 2.8 molar ratio of ethylene glycol to dimethyl 2,6-napthalene dicarboxylate, 60 ml/min of N2, amount of zinc acetate being 0.08 % / mole of dimethyl 2,6-napthalene dicarboxylate.

Particle Size Control, Structure and Magnetic Characterization of Cobalt Nanoparticles

2007 ◽  
Vol 998 ◽  
Author(s):  
Abhishek Singh ◽  
Nirav Parekh ◽  
Gregory Young ◽  
Kiumars Parvin ◽  
Maninder Kaur ◽  
...  
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Size Control ◽  
Reduction Reaction ◽  
Cobalt Nanoparticles ◽  
Molar Ratio ◽  
Ferromagnetic Behavior ◽  
Average Particle ◽  
Transmission Electron ◽  
Precursor Material

ABSTRACTCobalt nanoparticles were synthesized by means of a hot metal reduction reaction with cobalt chloride as precursor material. The size of cobalt nanoparticles was controlled by the choice of surfactant and the molar ratio of surfactant-to-reagent. Surfactants with larger alkane side chains yielded a smaller average nanoparticle size (diameter) and tighter size distribution, as these chains provided steric hindrance to the growth of the nanoparticles after initial nucleation. For each alkane side chain, a high molar ratio of surfactant-to-reagent (HSR) rendered nanoparticles with smaller particle size, while a low molar ratio of surfactant-to-reagent (LSR) produced larger nanoparticles. Measurements on transmission electron microscope images of cobalt particles synthesized with tri-octylphosphine revealed an average particle size of 6.9 nm (HSR) and 9.1 nm (LSR), while particles synthesized with tri-butylphosphine had a mean diameter of 12.5 nm (HSR) and 14.9 nm (LSR). X-ray diffraction profiles indicated that particles had metastable ε-cobalt structure. Room temperature magnetization measurements showed ferromagnetic behavior with highly square M-H loops indicative of single domain particles with coercive fields in the range of 400–500 Oe.

Process R&D for Particle Size Control of Molybdenum Oxide

2016 ◽  
Author(s):  
Sujat Sen ◽  
Trevor Dzwiniel ◽  
Krzysztof Pupek ◽  
Gregory Krumdick ◽  
Peter Tkac ◽  
...  
Keyword(s):  
Particle Size ◽  
Molybdenum Oxide ◽  
Size Control ◽  
Particle Size Control

scholarly journals Feasibility of fly ash as fluxing agent in mid- and low-grade phosphate rock carbothermal reduction and its reaction kinetics

2021 ◽  
Vol 10 (1) ◽  
pp. 157-168
Author(s):  
Biwei Luo ◽  
Pengfei Li ◽  
Yan Li ◽  
Jun Ji ◽  
Dongsheng He ◽  
...  
Keyword(s):  
Particle Size ◽  
Fly Ash ◽  
Reaction Time ◽  
Carbothermal Reduction ◽  
Industrial Waste ◽  
Phosphate Rock ◽  
Molar Ratio ◽  
Low Grade ◽  
Carbon Excess ◽  
Fluxing Agent

Abstract The feasibility of industrial waste fly ash as an alternative fluxing agent for silica in carbothermal reduction of medium-low-grade phosphate ore was studied in this paper. With a series of single-factor experiments, the reduction rate of phosphate rock under different reaction temperature, reaction time, particle size, carbon excess coefficient, and silicon–calcium molar ratio was investigated with silica and fly ash as fluxing agents. Higher reduction rates were obtained with fly ash fluxing instead of silica. The optimal conditions were derived as: reaction temperature 1,300°C, reaction time 75 min, particle size 48–75 µm, carbon excess coefficient 1.2, and silicon–calcium molar ratio 1.2. The optimized process condition was verified with other two different phosphate rocks and it was proved universally. The apparent kinetics analyses demonstrated that the activation energy of fly ash fluxing is reduced by 31.57 kJ/mol as compared with that of silica. The mechanism of better fluxing effect by fly ash may be ascribed to the fact that the products formed within fly ash increase the amount of liquid phase in the reaction system and promote reduction reaction. Preliminary feasibility about the recycling of industrial waste fly ash in thermal phosphoric acid industry was elucidated in the paper.

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