Nanotechnology for Energy and Environment BIOE298 DP

A major technological challenge for human race in 21 st century is the transition from fossil-fuel-based energy economy to renewable (sustainable) energy one. Collective energy demand of the planet is predicted to be doubled by the mid of 21st century and to be tripled by the end of this century. There is a urgent need to develop CO 2 - neutral energy sources. The sustainable energy alternatives should be cost effective. Sustainable Energy: Need a Major Breakthrough

Quantum size effects (atomic level of matter) result in unique mechanical, electronic, photonic, and magnetic properties of nanoscale materials Chemical reactivity of nanoscale materials greatly different from more macroscopic form, e.g., gold Vastly increased surface area per unit mass, e.g., upwards of 1000 m 2 per gram New chemical formation, e.g., fullerenes, nanotubes of carbon, titanium oxide, zinc oxide, other layered compounds The Importance of Nanoscale Properties

The melting point of gold particles decreases dramatically as the particle size gets below 5 nm For nanoparticles embedded in a matrix, melting point may be lower or higher, depending on the strength of the interaction between the particle and matrix.

Benefits already observed from the design of nanotechnology based products for renewable energy are: An increased efficiency of lighting and heating Increased electrical storage capacity. A decrease in the amount of pollution from the use of energy

Portfolio of solar/thermal/electrochemical energy conversion, storage, and conservation technologies, and their interactions Workshop on Nanotechnologies for Thermal and Solar Energy Conversion and Storage, August 10,11, 2008, Jacksonville, FL Opportunities of Nanoparticles for Energy and Environment

More efficient devices for… LED-based lighting Thermoelectric refrigeration Thermoelectric and thermo-photovoltaic conversion of waste heat Photovoltaic conversion of solar energy and production of hydrogen Other benefits Compact Robust Low environmental impact Challenges Efficiency breakthroughs needed! Availability and price of raw materials Manufacturing costs

Electricity generation accounts for about 37% of primary energy consumption in the U.S. Lighting accounts for 22% of the nation’s electric power usage. The DoE SSL Goal: a solid-state lamp that is more efficient, longer lasting and cost competitive compared to conventional technologies, targeting a system efficiency of 50% and the color quality of sunlight. Implications of Success: 33% reduction in energy consumed for lighting by 2025, eliminating need for MW power plants, and saving consumers $128 B+.

Low cost solution: Blue (In,Ga)N LED with partially absorbing yellow phosphor Limitations: poor color rendering, low efficiency due to Stokes shift Warm light solution: Board-level integration of (In,Ga)N/yellow phosphor and (Al,Ga,In)P red LEDs Limitations: “green gap”, high cost of assembly III-V LEDs cover the visible spectrum, but not with one materials system Compound Semiconductor, June 2008, pg. 17

Generate electricity directly from sunlight 2 Main types: – Single-crystal silicon (traditional) Widespread Expensive to manufacture – Dye-sensitized (“nano”) Newer, less proven Inexpensive to manufacture Flexible Photovoltaic Solar Cells Silicon-based solar cell Dye-sensitized solar cell

Problem: Fast energy loss by hot carriers – Hot carriers are produced when solar photons with energy significantly higher than the band gap of the semiconductor is absorbed. Excess energy leads to lattice vibrations and thus affects the efficiency. Solution 1: Use of Si nanocrystals with different band gap values to capture the full solar spectrum Solution 2: Use of quantum confined nanocrystals to generate multi-exciton generation

Organic dye sensitized solar cells Charge-carrier recombination problem can be addressed by using nanoparticle /nanostructures. Carrier collection efficiency can be improved by using one dimensional nanostructures such as nanowires and nanotubes. Nanotechnology may provide routes for cost reduction by using thin films.

Hydrogen from solar water splitting Photoreduction of CO 2 with water to form hydrocarbon (methane, methanol etc.) – This approach is very interesting as using CO 2 as a raw material to produce hydrocarbon fuels just by using sun light. – Negative CO 2 foot print – Not only interesting from the environment point of view, but also from the view of sustainable transportation using the existing Infra structure for fuel distribution

TiO2 nanoparticles are used in solar water splitting Increasing the efficiency of the process is a main challenge Oxynitride of TiO2 (TiO2-xNx) is a better alternative Nanosized TiO2-xNx can absorb in the visible region Solar Photocatalysis

Despite the huge advantages, their commercialization is hampered by: – High cost – Durability issues – Operability issues Solutions for some these bottlenecks will be from nanotechnology e.g.: Replacing Pt catalysts with some cheaper material in low temperature fuel cells Fuel Cells

What is the problem? Hydrogen fuel cell development has some practical issues associated with cost benefit and infrastructure development for safety and economics (e.g., fuel manufacturing, transportation, and storage). Although hydrogen has a high energy density by weight, it has a low energy density by volume as compared to hydrocarbon-based fuel cells. Thus, hydrogen storage is one of the bottlenecks for hydrogen fuel cell development since high-pressure compressed gas tanks are large and heavy. In addition, compressing hydrogen to high pressures require energy as well, defeating some of the cost benefits with fuel cells. Liquid hydrogen storage, which does not have a great energy density by volume as compared to hydrocarbon, also requires cryogenic storage – a bulky and expensive option.

a) Hydrogen production and storage by renewable resource, (b) hydrogen storage in metal doped carbon nanotubes, (c) storage in mesoporous zeolite: by controlling the ratio of different alkali metal ions (yellow and green balls), it is possible to tailor the pressure and temperature at which hydrogen is released from the material, (d) hydrogen storage in metal–organic framework (MOF)-74 resembles a series of tightly packed straws comprised mostly of carbon atoms (white balls) with columns of zinc ions (blue balls) running down the walls. Heavy hydrogen molecules (green balls) adsorbed in MOF-74 pack into the tubes more densely than they would in solid form. Hydrogen storage in tanks presently used in hydrogen-powered vehicles

Hydrgen gas (red) adsorbed in an array of carbon nanotubes (grey). The hydrogen inside the nanotubes and in the interstitial channels is at a much higher density than that of the bulk gas

The growth of large-area graphane-like film by RF plasma beam deposition in high vacuum conditions. Reactive neutral beams of methyl radicals and atomic hydrogen effused from the discharged zone and impinged on the Cu/Ti-coated SiO 2 /Si samples placed remotely. A substrate heating temperature of 650 °C was applied

a) STM images of graphane. The bright protrusions in the image are identified as atomic hydrogen clusters; (b) after annealing at 300 °C for 20 min; (c) after annealing at 400 °C for 20 min; (d) graphene recovered from graphene after annealing to 600 °C for 20 min. Scale bar 3 nm

Nanotech Materials for Truly Sustainable Construction  60% of global industrial waste is from the construction and demolition of buildings  60% of electrical use in developed nations is by buildings  40% of total energy consumed is by buildings

Old or new? (Damascus AD) Arms race? The first crusaders encountered better steel  Wootz steel, developed in India & Sri Lanka ~300 BC  greater strength & flexibility due to carbon nanotubes  technique lost ~1750AD

The Revolution in building science

A quick overview  Steel  Concrete  Glass  Gypsum Drywall  Fabrics & Carpet  Energy/HVAC  Filtration  Electronics / Sensors  Tools  Coatings & Paints  Lighting  Insulation Put on your running shoes…

Steel  Nanocomposite steel is available & stronger (per ASTM)  Withstands temperatures as low as -140F  Increased plasticity  Free of corrosion-causing carbide paths  Results:  reduced amount of steel  Simplified placement of structural concrete  20 to 40% savings

Concrete  Production of concrete accounts for 8% of total CO 2 emissions worldwide  Translucent concrete?

Glass  Can block UV & glare  Self-cleaning glass coated (titanium dioxide coating breaks down organic matter

Switchable Glass Switch!!

Gypsum Drywall  Nano-drywall is lighter, stronger and water resistant

Fabrics and Carpet  Nano-treatments are used on commercial fabrics  Color-fast, stain proof and dirt proof  Naturally hydrophobic, no mold or mildew

Energy / HVAC  Solar cells infused with nano-technology are thin, flexible and come in rolls so they can be applied as roofing material

Tools  Doped Nanophostate Lithium Ion batteries  Cordless tools are more powerful than corded!

Coatings and Paints  Nano particles enhance physical and aesthetic qualities  Hard, durable finish  Excellent water resistance  Scrub-ability  Stain blocking and other properties

LEDs (point source) & OLEDs (sheet)  40% of commercial energy goes to lighting  LED is most efficient, sustainable solution  10X more efficient than incandescent  50, ,000 hours (vs 10,000) Lighting "No other lighting technology offers so much potential to save energy and enhance the quality of buildings" U.S. Dept. of Energy

 46% average annual growth from  HB LED market $4.2 billion in 2006  Growing to $9.9 billion in 2011 Big technology push Solid-state lighting *Examples: Osram, Philips, OptiLED Holdings (Hong Kong)

Solid-state lighting

Insulation  Aerogel, a translucent thermal- acoustic insulator  Looks like frozen smoke  Best insulating solid in the world  Weighs only 90 grams per liter  Extremely flexible - blankets, beads, sheets The new “plastic”* *Not really—it’s amorphous silica (sand)

How to use these innovations? Steel Concrete Glass Gypsum Drywall Fabrics & Carpet Energy/HVAC Filtration Electronics / Sensors Tools Coatings & Paints Lighting Insulation

Sound Transmission : Acoustic Performance Truck Noise 10 db attenuation HZ sound transmission loss 2-3/4” FRP Sound pressure level vs. time Fiberglass insulation Nanogel ®

About aerogels  Well-known, insulating nano-substance that is translucent and 97% air  Nanogel TM* panels – developed for skylights –  Lightweight  Hydrophobic  Highly translucent  Thin  Superb thermal / acoustic insulator  Manufactured as large, rigid panels

Heat, Light, & Noise Noise  50% Sound Reduction Thermal Performance  R-20 The insulating value of a 6” stud wall Testing Permanence of performance  Non-combustible/ no smoke  Mold/mildew resistance  Condensation resistance  UV Stable

More about Aerogels  Nanomaterial known since 1931  Used extensively in aerospace  Nanogel TM is a proprietary form of “aerogel” - skylights - exterior glazing - pipeline insulation - apparel - medical devices

 Nanogel used across North America & nine European countries  Not an experiment!  Cabot is 125 years old, a $2.9 billion public company - 21 countries - 36 manufacturing sites - 8 R&D facilities More about Aerogels

Examples – Skylights

Application : a 25mm thick multi-wall polycarbonate sheets façade filled with nano-material (Total surface of 1450m2) on the whole perimeter of the building (surface of 3360m2). The façade had to meet a thermal insulation value < 2.7 W/m.K The nano-material allows to achieve a value of 0.89 W/m.K Applications

Shaders were not an option : very costly, heavy structure, not in line with the architect’s concept of a smooth building surface Shaders Options

Versus Double-pane Glass Glass, profiles : €300/m² €435,000 Shaders €130/m² €188,500 Total cost €430/m² €623,500 Versus PC without nanomaterial Polycarbonate sheets : €100/m² €145,000 Shaders €130/m² €188,500 Total cost €230/m² €333,500 Nano-material Solution + Polycarbonate Polycarbonate sheets : €100/m² €145,000 Nano-material cost : €67/m² € 97,000 Total cost €167/m² €242,000 Energy savings €3000/year on lighting €2000/year on heating Savings €263/m² €381,350 Immediate payback + €5,000/year on energy Savings €63/m² €91,500 Immediate payback + €5,000/year on energy Nano-Materials (aerogels) applied to the Building Industry Cost comparison

Nanotech Materials for Truly Sustainable Construction Results

Natural daylight evenly dispersed inside the building No glare, no shadow, no “light tunnel” issues High comfort level for the players and spectators Natural daylight evenly dispersed inside the building No glare, no shadow, no “light tunnel” issues High comfort level for the players and spectators Results

A new way of thinking  Photocatalytic cement with TiO 2  Self cleaning  Removes pollutants in area around building (CO 2, NO 2, etc.)

What is Nanogel? Aerogel resists the transfer of heat, making it a great insulator.

- Unsurpassed thermal insulation - R-value of 8 per inch / U-value of.64W/m²K per 25 mm’ - Increased natural light transmission - 75% per 3/8 inch / 80% per cm - Superior light diffusion – elimination of glare - Improved acoustic performance - Reduced solar heat gain/loss - Decreased energy consumption – heat, air conditioning, lighting, ventilation, carbon emissions - Unmatched moisture resistance – 100% hydrophobic - Exceptional color stability and insulation performance Nanogel Performance

100 µm10 µm1 µm100 nm10 nm1 nm0.1 nm Conventional Filtration Microfiltration Ultrafiltration Reverse Osmosis H 2 O (0.2 nm) Hemoglobin (7 nm) Virus ( nm) MicrobialCells (~1 µm) Protozoa (>2 µm) PM 2.5 Aerosols Nanoscale contaminants in water and air (little is known) Size Spectrum of Environmental Particles Pollens ( µm) Adenovirus 75 nm Bacteriophage 80 nm Influenza 100 nm E. Coli 1000 nm Fullerenes, nanotubes After Wiesner

Go to Publications/Proceedings

OZONE AND NANOTECHNOLOGY

Ozone Layer Depletions In the 70s it was discovered at the University of California Actually, it is not a hole but a decrease of the ozone layer’s thickness In the equatorial regions where the ozone layer always has been thinner, this decrease is more obvious.

The ozone hole grows and decreases every year with the stations, disappearing slowly as the south hemisphere reaches the maximum of his summer. Climatic Factors temperature Rainfalls The Problem

Why is The Ozone Hole Continue to GROW UP Since Montreal Protocol (1987) Small groups of the Chemical Industry, knowing that refrigerants will be banned, started to produce more. So, from 1990 to 1995 it was produced more since refrigeration with CFC’s started. CFC’s substances take a long time (10-15 years) to reach the ozone layer’s level

CFC’s (Freons) were invented in the 30s. The most commons are CFCl3 (freon 11), CF2Cl2 (freon 12), C2F3Cl3 (freon113) y C2F4Cl4 (freon 114). DESTRUCTION PROCESS Release chlorine of certain stable compounds, which is attacked by the intense UV radiation, can strip of an atom to the ozone molecule giving rise to ClO and normal oxygen. Each molecule of CFC destroys thousand and thousand of ozone molecules. As they are not very reactives, CFC’s spread slowly (it takes years) towards the stratosphere without undergo changes; there they decompose because of the UV radiation of λ= nm

Despite the fact that the growth-rate of ozone depletion potential (ODP) in the atmosphere is starting to drop, without Molecular Nanotechnology (MNT) the impact of ozone-depleting substances (ODS) on stratospheric ozone will continue. ODS refrigerants can be replaced with MNT → The growth-rate of ODP in the ODS reservoir will become zero. Drexler proposed using sodium-containing balloon type nanobots

The nanobots, powered by nano-solar cells, collect CFC’s and separate out the chlorine in the stratosphere. Combining this with sodium makes sodium chloride. When the sodium is gone, the balloon collapses and falls. Finally, a grain of salt and a biodegradable speck fall to Earth. The stratospheric CFC is quickly removed. There can be used also nanobots containing otherbmetals (Ca, Mg) to remove stratospheric CFC. Among ODS, halogens other than chlorine (Br) could be neutralized using this tecnique.

Metal Nanoparticle Solution to Ozone Depletion

NanostructureSize Example Material or Application Clusters, nanocrystals, quantum dots Radius: 1-10 nm Insulators, semiconductors, metals, magnetic materials Other nanoparticlesRadius: nm Ceramic oxides, Buckyballs NanowiresDiameter: nm Metals, semiconductors, oxides, sulfides, nitrides NanotubesDiameter: nm Carbon, including fullerenes, layered chalcogenides Jortner and C.N.R.Rao, Pure Appl Chem 74(9), , 2002 What are the materials of nanotech?

How can these properties be used to protect the environment? Nanomaterials have unique properties

Characterizing Nanomaterials

Applications of Nanotechnology

VDI

The Challenge Use nanotechnology research to: …Help clean up past environmental damage …Correct present environmental problems …Prevent future environmental impacts …Help sustain the planet for future generations

“Because of nanotechnology, we will see more change in our civilization in the next thirty years than we did during all of the 20 th century” - M. Roco, National Science Foundation The future of is here now

Resources  Material Connexion, Beylerian & Dent (Wiley, 2005)  Material Architecture, Fernandez (Oxford, 2006)  EU Nanoforum Report (December 2006; nannoforum.org)  Transmaterial, Brownell, (Princeton, 2006)  Material World 2, MateriO (Birkhauser, 2006)  Extreme Textiles, McQuaid (Princeton, 2005)  The Dance of Molecules, Sargent (Penguin, 2006)  The Nanomaterials Handbook, Gogotsi (CRC, 2006)