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Explore the unique properties of nanoparticle structures, their reactivity, and catalytic capabilities. Study the impact of surface energy on chemical and physical properties. Learn about extendable solids, reactivity, and adsorption in nanoscience.
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Metallic and Ionic Nanoparticles Extendable Structures: Reactivity, Catalysis, Adsorption
Nanoparticles HOW and WHY do these large numbers of surface atoms compared to interior atoms make nanoparticles so different?
Nanoparticles Think Coordination Numbers!
Nanoparticles Interior atoms Attracted to lots of nearest neighbors High Coordination Numbers
Nanoparticles Surface atoms Attracted to few nearest neighbors Low Coordination Numbers
Nanoparticles Surface atoms have Higher energy! E (surface atoms) • E (interior • atoms) = E (surface) Surface Energy!
Nanoparticles Metallic Crystal Nanoparticle Smaller Sample Larger Sample
Nanoparticles The surface …is where the interactions that result in changes in physical and chemical properties occur. …is where chemical reactions take place.
Nanoparticles Factors that affect the RATE of chemical reactions 1. Size of reaction particles and increasing surface area 2. Concentrations of reactants 3. Temperature 4. Presence of a catalyst
Nanoparticles What factors account for the increase in reaction rates of chemical processes at the nanoscale level? As the size of nanoscale particles decreases, the surface area to volume ratio increases. Therefore, the surface energy increases!
Nanoparticles Adsorption takes place at the surface.
Nanoparticles 7 grams of nanoparticles (four nm) have a surface area equivalent to a football field
Nanoparticles Catalytic reactions takes place at the surface.
Nanoparticles Nanowires Gold Catalytic Surface Scanning Electron Microscop (SEM) showing the vertical growth of nanowires on a gold catalytic surface for electronic devices (Stanford Nanofabrication Facility)
Metallic and Ionic Nanoparticles • Decreases in the size of particles • Increases in surface area Increase the rates of some chemical reactions
Nanoparticles Iron nanoparticles in YOUR backyard? http://www.phschool.com/science/science_news/articles/special_treatment.html
Making Connections • What chemical properties were most effected by surface energy? • How were the chemical properties affected by surface energy? • What physical properties might be affected by surface energy?
Module Flow Chart Lesson 1.1 What is Nanoscience? What is Nanoscience? Examine and Compare size: macro, micro, sub-micro (nano) SI prefixes Lesson 1.2 What Makes Nanoscience so Different? What makes Nanoscience so different? Compare Newtonian and Quantum Chemistry Regimes as they relate to nanoscale science Lesson 1.3 What Makes Nanoscience so Important? Interdisciplinary science The development of new technologies and instrumentation applications whose risk and benefits have yet to be determined Poster Assessment Students will further investigate the essential question that they have considered throughout the module: How and why do the chemical and physical properties of nanosamples differ from those of macrosamples? Lesson 2.1Extendable Solids As the size of the sample decreases the ratio of surface particles to interior particles increases in ionic and metallic solids Lesson 2.2Extendable Solids: Reactivity, Catalysis, Adsorption The difference between the energy at the surface atoms and energy of the interior atoms results in increased surface energy at the nanoscale Higher surface energy allowing for increased reactivity, adsorption, and catalysis at the nanoscale Lesson 2.3 Extendable Structures: Melting Point, Color Conductivity Lesson 3.1 Carbon Chemistry Lesson 3.2 Fullerenes and Nanotubes
