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Title: Silver Nanoparticles Synthesized by Microwave Heating: A Kinetic and Mechanistic Re-Analysis and Re-Interpretation

Journal Article · · Journal of Physical Chemistry. C
ORCiD logo [1]; ORCiD logo [2]
  1. Department of Chemistry, Middle East Technical University, 06800 Ankara, Turkey
  2. Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States

A quantitative kinetics and mechanistic reanalysis is performed of an important 2016 paper that described the formation of Agn nanoparticles from the polyol reduction of silver nitrate in the presence of poly(Nvinylpyrrolidone) under microwave heating. Elegantly and expertly obtained, in operando synchrotron high-energy X-ray diffraction (HEXRD) data, integrated with the microwave heating for the first time, were used to follow the Agn nanoparticle formation reaction in real time and to obtain time-resolved, HEXRD peak areas for the formation of both Ag(111) and Ag(200) facets. Unfortunately, the subsequent kinetics and mechanistic analysis that resulted is far from the state-of-the-art and was done without citing nor using wellestablished literature of nanoparticle nucleation and growth kinetics and mechanisms that has been available for over 20 years. Herein, the data are re-analyzed and re-interpreted in light of the fitting of the kinetics data with the presently most widely cited and employed, deliberately minimalistic, disproof-based nanoparticle nucleation and growth mechanism, dating back to 1997, of the pseudoelementary steps of slow continuous nucleation, A → B (rate constant k1), and then fast, autocatalytic surface growth, A + B → 2B (rate constant k2), where A is the starting Ag+ and B is the Ag0 product. The two pseudoelementary step mechanism is shown to be able to account for the previously reported kinetics data even for these large, up to ~100 nm (i.e., 0.1 μm) Agn nanoparticles, a remarkable result in its own right given that there are on the order of ~107 Ag(0) atoms in a ~100 nm particle formed from the reduction of ~107 Ag+ atoms in what must be >107 actual elementary steps. However, the k2 rate constant in particular likely loses much of its value since it is an average over a large change in the percentage of surface atoms in the growing nanoparticle. The results lead to nine revisions of questionable to incorrect previous claims and conclusions, plus a series of eight insights and guidelines for future work in nanoparticle formation kinetics and mechanism. An extensive Supporting Information further discusses interesting questions regarding the issues in analyzing and understanding nanoparticle formation kinetics and the mechanism of such large, ~0.1 μm-sized particles.

Research Organization:
Colorado State Univ., Fort Collins, CO (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences, and Biosciences Division
Grant/Contract Number:
FG402-03ER15453; FG02-03ER15453
OSTI ID:
1415067
Alternate ID(s):
OSTI ID: 1529569
Journal Information:
Journal of Physical Chemistry. C, Journal Name: Journal of Physical Chemistry. C Vol. 121 Journal Issue: 49; ISSN 1932-7447
Publisher:
American Chemical SocietyCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 26 works
Citation information provided by
Web of Science

References (41)

Transition-metal nanocluster stabilization for catalysis: A critical review of ranking methods and putative stabilizers journal May 2007
A More General Approach to Distinguishing "Homogeneous" from "Heterogeneous" Catalysis: Discovery of Polyoxoanion- and Bu4N+-Stabilized, Isolable and Redissolvable, High-Reactivity Ir.apprx.190-450 Nanocluster Catalysts journal October 1994
A rapid, high-yield and large-scale synthesis of uniform spherical silver nanoparticles by a microwave-assisted polyol process journal January 2015
Is It Homogeneous or Heterogeneous Catalysis? Identification of Bulk Ruthenium Metal as the True Catalyst in Benzene Hydrogenations Starting with the Monometallic Precursor, Ru(II)(η 6 -C 6 Me 6 )(OAc) 2 , Plus Kinetic Characterization of the Heterogeneous Nucleation, Then Autocatalytic Surface-Growth Mechanism of Metal Film Formation journal August 2003
Synthesis of silver nanoplates at high yields by slowing down the polyol reduction of silver nitrate with polyacrylamide journal January 2007
The Kinetic Rate Law for the Autocatalytic Growth of Citrate-Stabilized Silver Nanoparticles: AUTOCATALYTIC GROWTH OF CITRATE-STABILIZED SILVER NANOPARTICLES journal April 2015
Nanoparticle Nucleation Is Termolecular in Metal and Involves Hydrogen: Evidence for a Kinetically Effective Nucleus of Three {Ir 3 H 2 x ·P 2 W 15 Nb 3 O 62 } 6– in Ir(0) n Nanoparticle Formation From [(1,5-COD)Ir I ·P 2 W 15 Nb 3 O 62 ] 8– Plus Dihydrogen journal April 2017
Synthesis of Ag Nanocubes 18–32 nm in Edge Length: The Effects of Polyol on Reduction Kinetics, Size Control, and Reproducibility journal January 2013
Transition Metal Nanocluster Formation Kinetic and Mechanistic Studies. A New Mechanism When Hydrogen Is the Reductant:  Slow, Continuous Nucleation and Fast Autocatalytic Surface Growth journal October 1997
A Mechanism for Transition-Metal Nanoparticle Self-Assembly journal June 2005
Formation Mechanism of Gold Nanoparticles Synthesized by Photoreduction in Aqueous Ethanol Solutions of Polymers Using In Situ Quick Scanning X-ray Absorption Fine Structure and Small-Angle X-ray Scattering journal January 2016
Platinum-Catalyzed Phenyl and Methyl Group Transfer from Tin to Iridium:  Evidence for an Autocatalytic Reaction Pathway with an Unusual Preference for Methyl Transfer journal February 2008
Reply to Comment on “Fitting and Interpreting Transition-Metal Nanocluster Formation and Other Sigmoidal-Appearing Kinetic Data: A More Thorough Testing of Dispersive Kinetic vs Chemical-Mechanism-Based Equations and Treatments for 4-Step Type Kinetic Data” journal March 2010
Quantifying the Nucleation and Growth Kinetics of Microwave Nanochemistry Enabled by in Situ High-Energy X-ray Scattering journal December 2015
Supersensitivity of Transition-Metal Nanoparticle Formation to Initial Precursor Concentration and Reaction Temperature: Understanding Its Origins journal March 2008
Nanocluster Formation Synthetic, Kinetic, and Mechanistic Studies. The Detection of, and Then Methods To Avoid, Hydrogen Mass-Transfer Limitations in the Synthesis of Polyoxoanion- and Tetrabutylammonium-Stabilized, Near-Monodisperse 40 ± 6 Å Rh(0) Nanoclusters journal September 1998
Novel Polyoxoanion- and Bu4N+-Stabilized, Isolable, and Redissolvable, 20-30-.ANG. Ir300-900 Nanoclusters: The Kinetically Controlled Synthesis, Characterization, and Mechanism of Formation of Organic Solvent-Soluble, Reproducible Size, and Reproducible Catalytic Activity Metal Nanoclusters journal September 1994
Sigmoidal Nucleation and Growth Curves Across Nature Fit by the Finke–Watzky Model of Slow Continuous Nucleation and Autocatalytic Growth: Explicit Formulas for the Lag and Growth Times Plus Other Key Insights journal February 2017
Quantitative mineralogical analysis of carbonate sediments by X-ray diffraction: a new, automatic method for sediments with low carbonate content journal August 1982
Mass Absorption Corrected X-Ray Powder Diffractograms. Part 1: Measuring Pyrite in Powdered Coals journal March 1990
A new approach causing the patterns fabricated by silver nanoparticles to be conductive without sintering journal August 2012
Crystallisation Kinetics of Metal Organic Frameworks From in situ Time-Resolved X-ray Diffraction journal September 2013
Kinetic Factors in the Synthesis of Silver Nanoparticles by Reduction of Ag + with Hydrazine in Reverse Micelles of Triton N-42 journal August 2013
Microwave Enhancement of Autocatalytic Growth of Nanometals journal October 2017
Nanocluster Size-Control and “Magic Number” Investigations. Experimental Tests of the “Living-Metal Polymer” Concept and of Mechanism-Based Size-Control Predictions Leading to the Syntheses of Iridium(0) Nanoclusters Centering about Four Sequential Magic Numbers journal December 1997
Continuous synthesis of monodispersed silver nanoparticles using a homogeneous heating microwave reactor system journal January 2011
Kinetics of the Formation of Silver Dimers: Early Stages in the Formation of Silver Nanoparticles journal March 2011
Transition-Metal Nanocluster Size vs Formation Time and the Catalytically Effective Nucleus Number: A Mechanism-Based Treatment journal September 2008
Microwave synthesis of branched silver nanowires and their use as fillers for high thermal conductivity polymer composites journal March 2016
Thermal Decomposition of Silver Acetate: Physico-Geometrical Kinetic Features and Formation of Silver Nanoparticles journal April 2016
The Four-Step, Double-Autocatalytic Mechanism for Transition-Metal Nanocluster Nucleation, Growth, and Then Agglomeration: Metal, Ligand, Concentration, Temperature, and Solvent Dependency Studies journal March 2008
Nanocluster Formation and Stabilization Fundamental Studies:  Ranking Commonly Employed Anionic Stabilizers via the Development, Then Application, of Five Comparative Criteria journal May 2002
Fitting and Interpreting Transition-Metal Nanocluster Formation and Other Sigmoidal-Appearing Kinetic Data: A More Thorough Testing of Dispersive Kinetic vs Chemical-Mechanism-Based Equations and Treatments for 4-Step Type Kinetic Data journal October 2009
Nanoimprinted Semitransparent Metal Electrodes and Their Application in Organic Light-Emitting Diodes journal May 2007
Transition-Metal Nanocluster Stabilization versus Agglomeration Fundamental Studies: Measurement of the Two Types of Rate Constants for Agglomeration Plus Their Activation Parameters under Catalytic Conditions journal April 2008
Is There a Minimal Chemical Mechanism Underlying Classical Avrami-Erofe’ev Treatments of Phase-Transformation Kinetic Data? journal October 2009
Polyol Synthesis of Silver Nanostructures:  Control of Product Morphology with Fe(II) or Fe(III) Species journal August 2005
Strong Inference: Certain systematic methods of scientific thinking may produce much more rapid progress than others journal October 1964
Nucleation is Second Order: An Apparent Kinetically Effective Nucleus of Two for Ir(0) n Nanoparticle Formation from [(1,5-COD)Ir I ·P 2 W 15 Nb 3 O 62 ] 8– Plus Hydrogen journal December 2014
Analysis of reaction kinetics in the photomechanical molecular crystal 9-methylanthracene using an extended Finke–Watzky model journal January 2016
Additional Investigations of a New Kinetic Method To Follow Transition-Metal Nanocluster Formation, Including the Discovery of Heterolytic Hydrogen Activation in Nanocluster Nucleation Reactions journal January 2001