Nanoparticles Nanoparticles as Catalysts in Chemical Reactions

Nanoparticles asCatalysts in ChemicalReactionsGroup 2

Nanoparticles• a particle with a diameter in the range of 1-100100 nanometers(10^-9 meters).• behave like a whole unit in terms of its properties.p• a large surface area to volume ratio.• allows the particles to be more reactive.ncem.lbl.gov/images/OAM/nanoparticle.jpg

Nanoparticles• significantly differentproperties then thematerial they makeup.• Special propertiespaffect the propertiesof the wholematerial.• Often referred to asclusters.http://www.nanophase.com/UserFiles/image/web%20%20nanoparticles%201.jpg

Nanoparticles• variety it of shapes such asspheres, cylinders, platelets,tubes, etc.• designed d with modifieddsurfaces designed to meetthe need of their specificapplication.• enormous diversity can beused to make this animportant t active field ofscience.Nanoparticles Synthesis, Stabillization, passivation andFunctionalization Ramanathan Nagarajan and T. Alan Hatton Aug2008

Synthesis of Nanoparticles• synthesized db by a variety of methods using gas, liquid, idorsolid phase processes.• Such as flame pyrolysis, y high temperature evaporation, andplasma synthesis.Mechanism of nanoparticle production using vapor phase of liquid phase/collodialMechanism of nanoparticle production using vapor phase of liquid phase/collodialmethods.Nanoparticles Synthesis, Stabillization, passivation andFunctionalization Ramanathan Nagarajan and T. Alan Hatton Aug2008

Assembling NanoparticlesAssembling nanoparticles for applications:(a) Nanoparticles with stabilizing polymer • assembled in one, two or threemolecules around them in a random threedimensions, similar to howdimensional arrangement to create a porousnanoparticle system for catalytic oratoms and molecules areadsorption applicationsassembled into matter.(b) Nanoparticles assembled on apolyelectrolyte or DNA molecule to serve as• specified locations on substratea nanoelectrical wire.to address and connect them to(c) Nanoparticles assembled on a blockthe macroscopic outside worldcopolymer patterned surface withnanoparticles located at the domainboundaries for a sensor applicationNanoparticles Synthesis, Stabillization, passivation andFunctionalization Ramanathan Nagarajan and T. Alan Hatton Aug2008

Intro to Catalyst• Back in the early 1800's it was observed that certain chemicals can speed upa chemical reaction – a process that became known as catalysis and that hasbecome the foundation of the modern chemical industry.• By some estimates 90% of all commercially produced chemical productsinvolve catalysts t at some stage in the process of their manufacture.http://upload.wikimedia.org/wikipedia/commons/thumb/5/58/Rowlandson_-_Chemical_Lectures.jpg/400px-Rowlandson_-_Chemical_Lectures.jpg

What Catalyst do• Lower activationenergy of the reaction• Provides an alternatereaction pathway toget the products• Increases the rate of areaction because ittakes less energy toinitiate the forwardreactionhttp://www.biodieselchem.com/Portals/6/Energy%20Input.jpg

Catalysis•lower the rate-limiting free energy change to a morefavorable transition rate•Examples: transition metals and certain activated kinds ofcarbon.http://depts.washington.edu/centc/Images/CatalysisCurve2009.jpg

Biochemical Catalysts•Most biochemical processes arecatalyzed with enzymes acting as thecatalysts.•These enzymes are very important innatural processes of the body.http://universe-review.ca/I11-05-emzyme.jpg

Nanoparticle Catalysts• Nature reactive due to the largesurface are per volume.• This reactive nature makesnanoparticles a natural choicefor catalysts.• Using various preparationmethods nanoparticles can becustom designed in order toserve a specific purpose.• Biological nanoparticles havebeen used in nature since thebeginning of life.• Particle size has large impact ofeffectiveness of catalyst.http://www.physorg.com/newman/gfx/news/newnanoparti.jpgh / / / / ti

Nanocatalyst Categories• four main categories based on composition.• Platinum or Palladium Based:Ex. Pt/Ru/Ni,• Gold Based:Ex. Au/TiO2, Au/MgO• Other Metal NanoparticleBased:Ex. Cu, Rh, V-Mg-O• Dispersed in Polymers:Ex. Pt/polypyrrole, l Cu/Polyanilinehttp://www.julianhewitt.com/wordpress/wp-content/uploads/2008/03/platinumore.jpg

Pt/Pd Nanoparticle Catalysts•The most common application of Pt/Pd nano-catalysts is the automotive catalyticconverter.•Also used in polymers, textiles, and solar energy materials•A major point of research in Pt/Pd nano-catalyst research is in the biomedical field•Platinum based metal nanoparticles are critical in fuel cell technology where cheapeffective catalysts are in great demand.http://image.truckinweb.com/f/8330265/0708tr_22_z+2001_ford_f150_super_crew+broken_catalytic_converter.jpg

Gold Nanoparticle Catalysts• Gold as a material ischemically inert(stable)and generally regardedas a poor catalyst.• Masake Haruta resentlypublished a paper in ascientific journaldescribing how goldcan be an effectivecatalyst at nanoparticlesizes.• Haruta argues that thecatalytic properties ofgold depend on threemain factors:1. Contact Structure2. Support Selection3. Particle Sizehttp://www3.interscience.wiley.com/cgi-bin/fulltext/104529618/main.html,ftx_absImage shows catalytic activity for theoxidation of H2 as a function of temperature.Traditional Gold requires a high h temperature tto even become a poor catalyst.

Gold Nanoparticle Catalystshttp://www3.interscience.wiley.com/cgibin/fulltext/104529618/main.html,ftx_abs• Haruta proved that gold can be a very potent catalyst when impregnated on other surfaces.• Impregnating various metals with gold nanoparticles resulted in an effective catalyst for the following types ofreactions:1. Complete Oxidation2. Oxidative decompostion3. Redecution of NOx4. Oxidation or reduction of COx5. Selective oxidation6. Selective Hydrogenation7. HydroChlorination• Percent of conversion is highly dependany on Catalytic Metal Loading Percent and Mean Particle Diameter.

Gold Nanoparticle Catalysts• Effective particle size for goldNanocatalyst is less than 5 nm.• Decrease of the surface arecoordination number and themobility of surface gold atomslead to greater reactivity.• Contact structure is importantbecause it governs theavailability and order of thegold atoms.• Gold nanoparticle catalystsremain effective at lowtemperatures.http://www.livbit.com/article/wp-content/uploads/2008/12/gold-nanoparticles.jpg

Other Metal NanoparticleCatalysts• A sample nanoparticle catalyst for the oxidation of methanol is Pt/Ru/Ni nanoparticle alloys.• Nanoclusters of silver atoms have been proven to be effective catalyst for ethyleneepoxidation.• Cluster of atoms are restricted by their method of creation, for example e-beam constructionof nanoclusters results in a minimum particle size of 20nm.• It has also been reported that the addition of base metals such as iron, cobalt and nickel toplatinum also improves the oxygen-reduction reaction rate, but these kinds of base metalsdissolve easily in the acidic environment of a PEFC where the catalyst is working, which is aproblem.http://www.indiana.edu/~bdlab/images/cryovlp.jpg

Nanoparticle Preparation• Preparing a nanoparticle catalyst involves somehowmounting the particles onto a support structure.• The main hurdle in Nanoparticles creation is the lack ofcontrol over shape, size and stability.• Ideally the Nanocatalyst should ldb be stable and have veryprecise dimensions.• The various preparation p routes for creating nanoparticlecatalysts are:• Physical• Chemical• Physicochemicalhttp://www.ims.demokritos.gr/img_research/Dimosthenis1.JPGhttp://chemistry.dal.ca/Images/Zhang/fig1.jpg

Nanoparticle PreparationChemical Methods• Chemical methods of attaching nnprtil nanoparticles to support materials are:• Co-precipitation• Deposition-precipitationprecipitation• Ion-exchange• Impregnation• Successive Reduction• Calcinations• Surface Capping• Microemulsions• Photochemistry• Chemical Vapor Deposition• Electrochemical Reduction• Etc• Chemical techniques are the oldest andhave been proven to be successful.Nanoparticles Synthesis, Stabillization, passivation and FunctionalizationRamanathan Nagarajan and T. Alan Hatton Aug 2008

Nanoparticle Preparation• Impregnation- a metal nanoparticle precursordissolved in a solvent.- added to a porous support so that athick slurry is formed.- The solvent is then removed and thesolid is recovered and tested.• Co-precipitation- the metal and its support precipitatefrom solution at the same time.- Using this method metal nanoparticlescan become imbedded diinto porousmaterials.• Precipitation-Deposition- the dissociation of the metal precursorfollowed by a change in pH toprecipitate the nanoparticles onto thesurface of a support.Chemical Methodshttp://www3.interscience.wiley.com/cgi-bin/fulltext/121637625/main.html,ftx_abs

Nanoparticle PreparationChemical Methods• Microemulsions- Microemulsions are similar toimpregnation however the metal salt isdissolved in a emulsion which thenimpregnates the porous supportstructure. This method has resulted ingreater control of particle size.• Photochemistryh t- Photochemistry involves a high wattagelight source in order to excite moleculesand add energy to reactions. Theadditional energy allows for depositionsthat might not normally occur.http://www.fbi.gov/hq/lab/labannual05/page_iiic.jpg• Chemical Vapour Deposition- This method involves the vaporizationof metals followed by the formation andgrowth of nanoparticles under vacuumconditions. This method allows for awide variety of support structures.

Nanoparticle PreparationSurface Capping• Surface capping is an emergingsolution to some of thelimitation of conventionalchemical nanoparticlepreparation.• Surface capping employeespolymeric or molecular cappingagents to increase control overnanoparticle size and surfaceproperties.• Nanoparticles formed are oftenin a shell structure with themetal tl at tththe core and dththepolymers as the outside layer.• By controlling the amount ofcapping agent nanoparticleshape, size and stability can becontrolled.http://www.molecularassembler.com/Papers/PDMM/Slide68.GIF

Nanoparticle PreparationPhysical Methods• Physical and Physicochemicalh techniques generally involvemore expensive technology butpromise more control overnanoparticle creation.• The main physical methods forcreating nanoparticle catalystsare:- Sonochemistry- Microwave Irradiationi- Pulsed Laser Ablation- Supercritical Fluids- Plasma- Etc.http://ag.arizona.edu/swes/rasmussen/pics/XRD_pics/DSC02074.JPG

Nanoparticle PreparationPhysical Methods• Sonochemistry uses sonic waves toalter molecule properties. affect thesurface structure of the metalsusually enhancing the surfacecontact area.• Microwave Irradiation involvesexposing metal salt solutions tomicrowave irridiation in order toprepare a wide range ofnanocatalysts.• Supercritical fluids can be employedto create supported nanoparticlecatalysts by providing a solutionwith a lower viscosity it and lesssurface tension.http://www.bloodhoundssc.com/_db/_images/sonic_boom.jpg

New AdvancementsFuel CellsCarbon Nanotubeshttp://www.chem.umass.edu/masscrest/fuelingthefuture/images/fuelcell.jpghttp://neurophilosophy.files.wordpress.com/2006/08/multiwall-large.jpg

Fuel Cells• A new type of catalystcreated tdbby surrounding ananoparticle of ruthenium(Ru) with one to twolayers of platinum (Pt)atoms.• Improves a key hydrogenpurification reaction andleaves more hydrogenavailable to make energy inthe fuel cell.www.cafcp..org

Fuel Cells• began with relatively largeplatinum particles scattered ona carbon surface.• oscillating voltage, whichinduces alternating chemicalreactions that determinewhere platinum atoms willaccumulate and where theywon't.• layer of platinum oxide formson other parts of thenanoparticle, protecting ti them.• The resulting 24-sided shapes,called tetrahexahedra, were thefirst such shapes formedartificially in metals, saysZhong Lin Wang, professorof materials science andengineering i at Georgia Tech.http://www.technologyreview.com/files/10884/catalyst_x220.jpg

CNT’s (Carbon Nano Tubes) as• Researchers at the FritzHaber Institute of theMax Planck Society inBerlin have been workingfor some time at metal-free catalysis usingnanocarbons.• While their focus initiallyhas been on ethylbenzene,an aromatic hydrocarbonthat plays an importantrole as an intermediate inthe production of variousplastic materials, they nowhave, for the first time,used carbon nanotubes(CNTs) to activate butane.Catalysthttp://scitizen.com/cacheDirectory/HTMLcontributions/img/Artist%20vision%20of%20nanotube.gif

CNT cont’d• CNTs can make certain important chemical reactions more effective, more energy efficient, and safer.• "Carbon nanotubes were used as catalysts before, for instance in converting ethylbenzene into styrene, aprecursor to polystyrene, an important synthetic material" Dr. Dangsheng Su explains to Nanowerk.• "But butane is much less reactive than ethylbenzene and we were surprised how well it worked – the highselectivities we observed were unexpected."http://endomoribu.shinshu-u.ac.jp/research/cnt/images/cat_cnt.jpg

Other Catalyst Uses• One popular industry that uses nano-catalysts is the energyprocessing field.• Petroleum refineries and automobiles use this technology.• Biodiesel and biofuels use both inorganic and biocatalysts.http://www.lansdownephotography.co.uk/assets/photos/industrial/Chemical%20Plant.jpg

Other Catalyst Uses• BlkBulk and dfifinechemicals areproduced throughcatalytic reaction.• Fine chemicals usemore nano-catalysts than bulk.• This is becausefine chemicals areusually for researchand require moreexpensive nano-particles.http://www.ndsu.edu/research/images/Generic_scientist_blue.JPG

Other Catalyst Uses• The most researchedarea of nano-catalystsisthatofthat biocatalysis.• Food processingthings like margarineuse nano-catalysts.• Scientists areresearching the roleof nano-catalysts inthe medical field.http://www.ccgov.net/departments/HR/images/medical%20symbol.gif

Why have nanocatalysts?• Catalyzing reactions canaffect a variety ofapplications in domainssuch as refining of oil, fuelcells, renewable energy,ground water remediation,catalytic converters,chemical and polymermanufacturing,pharmaceutical andbiomedical applications,food processing, paperand pulp recycling, andtextile production.Nanocatalyst technologycould well be the solution tothe many ensuing challengesthat range from processefficiencies to breadth ofproduct applications.http://www.eimcowatertechnologies.com/fandb/images/stories/recyclingimages/recycle%20symbol%20copy.png

Why have nanocatalysts?• Despite several factors propelling p the development of nn nanocatalysts tl t and theiradoption in numerous applications, technological challenges that the sector is yet toaddress include maintaining nanocatalyst stability and activity, agglomeration ofnanoparticles, control of the size nanoclusters, and reusability of nanocatalysts.http://www.physorg.com/newman/gfx/news/newnanoparti.jpghttp://www.atm.ch.cam.ac.uk/~paul/

Works Cited• http://carefreeenzymes.com/sitebuildercontent/sitebuilderpictures/EnzymeExample.jpg• http://image.truckinweb.com/f/8330265/0708tr_22_z+2001_ford_f150_super_crew+broken_catalytic_converter.jpg• http://www.americanelements.com/ptnp.html• http://www.ndsu.edu/research/images/Generic_scientist_blue.JPG• http://www.inplacemachiningjvic.com/images/industries_refinery.jpg• http://www3.interscience.wiley.com/cgi-bin/fulltext/88013153/PDFSTART/ / / /• http://www.springerlink.com/content/n7v6851033871433/fulltext.pdf• http://en.wikipedia.org/wiki/Nanoparticle• http://en.wikipedia.org/wiki/Catalysis• http://books.google.com/books?id=21OcPcgGNr4C&pg=PA120&lpg=PA120&dq=types+of+nanoparticle+catalysts&source=bl&ots=gF7IIbdzQq&sig=03D9rjkHNGaq3WeQ4UOW_CN4SF0&hl=en&ei=_ZLTSujgN4WiswPErdXvCw&sa=X&oi=book_result&ct=result&resnum=1&ved=0CBAQ6AEwAA#v=onepage&q=types%20of%20nanoparticle%20catalysts&f=false• http://www3.interscience.wiley.com/cgi-bin/fulltext/104529618/HTMLSTART• http://www3.interscience.wiley.com/cgi-bin/fulltext/121637625/HTMLSTART

Works Cited• http://www.purchon.com/chemistry/catalyst.htmpurchon com/chemistry/catalyst htm• http://www.chem4kids.com/files/react_catalyst.html• http://www.astro.virginia.edu/class/oconnell/astr121/cosmic-history-narrative.html• http://www.eso.org/public/events/astro-evt/DeepImpact/Impact/obseso4.htmlevt/DeepImpact/Impact/obseso4.html• http://www.engin.umich.edu/dept/che/research/linic/projects-au-support.html• MRS – Symposium Proceedings Vol. 900 – Nanoparticles and Nanostructures in Sensors and Catalysis – Fall 2005• http://neurophilosophy.files.wordpress.com/2006/08/multiwall-large.jpglarge.jpg• http://www.nanowerk.com/spotlight/spotid=7576.php• http://www.technologyreview.com/nanotech/18669/?a=f• http://www.news.wisc.edu/1492• http://www.sciencedaily.com/releases/2009/03/090319102321.htm• http://lpc1.clpccd.cc.ca.us/lpc/rschmidt/index.html• Nanoparticles Synthesis, Stabillization, passivation and Functionalization Ramanathan Nagarajan and T. Alan Hatton

NanoParticle CatalystsNanoParticleCatalystsGroup 2Archie Buchman, Kelly BufordJonathan Campoverde, Michael Dean,Snthesis Synthesis Purpose New Advances Categories Oerie OverviewChemicalIncrease ProcessEfficiencyCarbonNanotubesPt/RdWhat is aCatalystPhysicalLower ProcessCostFuel CellsGoldWhat is aNanoparticlePhysicochemicalEnable newProcessesOther MetalPolymerhttp://www.nd.edu/~gezelter/Main/floating-nanoparticle.jpg