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Manganese Oxide Nanoparticle Synthesis by Thermal Decomposition of ManganeseII Acetylacetonate
Published on: June 18, 2020
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Mechanism of Nanoparticle Formation in the Liquid-Phase Thermal Decomposition Method
Abhiram Y Singapati1, C Ravikumar1
1Colloids and Nanomaterials Laboratory, Department of Chemical Engineering, Visvesvaraya National Institute of Technology, South Ambazari Road, Nagpur 440010, Maharashtra, India.
Langmuir : the ACS Journal of Surfaces and Colloids
|June 28, 2023
Summary
This study proposes a new nanoparticle (NP) formation mechanism based on thermal energy equilibration, revealing multiple nucleation events and varied growth pathways in iron oxide NP synthesis. This understanding enables the creation of anisotropic nanoparticles without shape-directing agents.
Area of Science:
- Materials Science
- Nanotechnology
- Chemical Engineering
Background:
- Current nanoparticle (NP) formation models in liquid-phase thermal decomposition often assume a single, instantaneous nucleation event followed by monomer addition.
- This prevailing mechanism may not fully capture the complexity of NP synthesis, particularly under varying thermal conditions.
Purpose of the Study:
- To propose a generalized nanoparticle formation mechanism based on thermal energy equilibration for the heat-up synthesis route.
- To investigate the influence of thermal energy, ligands, heating rate, and aging time on NP nucleation and growth.
- To demonstrate the application of this mechanism in synthesizing anisotropic nanoparticles without shape-directing agents.
Main Methods:
- Extensive investigations using the heat-up method for iron oxide nanoparticle synthesis.
- Analysis of nanoparticle nucleation and growth dynamics under controlled thermal conditions.
- Systematic variation of parameters including energy input, ligand type, heating rate, and aging period.
Main Results:
- Multiple nucleation events were observed when thermal energy remained constant or varied minimally, contrary to the single nucleation assumption.
- Nanoparticle growth was found to occur via coagulation and/or monomeric addition, influenced by the aggregation barrier.
- The proposed mechanism successfully guided the synthesis of anisotropic iron oxide nanoparticles without shape-directing agents.
- Analogous formation pathways were identified in hot-injection and seed-mediated growth protocols.
Conclusions:
- A generalized nanoparticle formation mechanism based on thermal energy equilibration provides a more comprehensive understanding of NP synthesis in liquid-phase thermal decomposition.
- Controlling thermal energy and associated parameters allows for tailored nanoparticle nucleation and growth, enabling the synthesis of specific morphologies like anisotropic particles.
- The proposed mechanism is applicable across different synthesis protocols, including hot-injection and seed-mediated growth, highlighting its fundamental nature.
