Tag Archives: photocatalysis

3D nanotech blankets for clean drinking water?

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A March 24, 2025 news item on ScienceDaily announces a new technique for removing pollutants from water (aka, water remediation),

Researchers have developed a new material that, by harnessing the power of sunlight, can clear water of dangerous pollutants.

Created through a combination of soft chemistry gels and electrospinning — a technique where electrical force is applied to liquid to craft small fibers — the team constructed thin fiber-like strips of titanium dioxide (TiO₂), a compound often utilized in solar cells, gas sensors and various self-cleaning technologies.

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A March 24, 2025 Ohio State University (OSU) news release (also on EurekAlert), which originated the news item, delves further into the topic, Note: Links have been removed,

Despite being a great alternative energy source, solar fuel systems that utilize TiO₂ nanoparticles are often power-limited because they can only undergo photocatalysis, or create chemical reactions, by absorbing non-visible UV light. This can cause significant challenges to implementation, including low efficiency and the need for complex filtration systems. 

Yet when researchers added copper to the material to improve this process, their new structures, called nanomats, were able to absorb enough light energy to break down harmful pollutants in air and water, said Pelagia-Irene Gouma, lead author of the study and a professor of materials science and engineering at The Ohio State University. 

“There hasn’t been an easy way to create something like a blanket that you can lay on water and start creating energy,” she said. “But we are the only ones who have made these structures and the only ones to demonstrate that they actually work.”

The study was recently published in the journal Advanced Science. 

When titanium dioxide absorbs light, electrons are formed that oxidize water and attack pollutants, slowly destroying them until they become benign. When copper is added, that process is supercharged, making it even more effective. 

To determine this, researchers worked to characterize the nanomat’s updated properties to understand how it behaved and what made it different from other self-cleaning nanoparticles, said Gouma. Surprisingly, researchers found that compared to traditional solar cells, these nanomats can be more successful at power generation when placed under natural sunlight, she said.

“These nanomats can be used as a power generator, or as water remediation tools,” she said. “In both ways, you have a catalyst with the highest efficiency reported to date.”

These lightweight, easy-to-remove fiber mats can float and operate atop any body of water and are even reusable through multiple cleaning cycles. Because nanomats are so effective, researchers envision that they could be used to rid water of industrial pollutants in developing countries, turning otherwise contaminated rivers and lakes into sources of clean drinking water. 

Additionally, because this technology doesn’t generate any toxic byproducts like some solar cell systems, nanomats are extremely environmentally friendly. “It’s a safe material, it won’t hurt anything, and it’s as clean as it can be,” said Gouma. 

Still, although this team’s technology is incredibly efficient, how long it will take to scale up commercially depends on how quickly industries take notice of the product. “We have the tools to make them in large quantities and translate them to various industries,” said Gouma. “The only limitation is that it needs someone to take advantage of these abundant resources.”

Overall, the study’s findings suggest that nanomats could be a promising tool in many future photocatalytic applications, including long-term sustainability efforts like environmental remediation as well as solar-driven hydrogen production. 

In the meantime, the team plans to examine ways to optimize the material further. 

“This material is completely novel in terms of a new form of nanotechnology,” said Gouma. “It’s really impressive and something that we are very excited about.”

Other Ohio State co-authors include Fateh Mikaeilia and Mohammad Mahafuzur Rahaman. This study was supported by the National Science Foundation. 

Here’s a citation for and a link to the paper,

3D Self-Supported Visible Light Photochemical Nanocatalysts by Fateh Mikaeili, Mohammad Mahafuzur Rahaman, Pelagia-Irene (Perena) Gouma. Advanced Science Online Version of Record before inclusion in an issue 2502981 DOI: https://doi.org/10.1002/advs.202502981 First published: 24 March 2025

This paper is open access.

Wall paint that’s self-cleaning

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Who hasn’t had dingy walls? It seems there may be a solution at some point in the future according to a March 25, 2024 news item on ScienceDaily,

Typically, beautiful white wall paint does not stay beautiful and white forever. Often, various substances from the air accumulate on its surface. This can be a desired effect because it makes the air cleaner for a while — but over time, the colour changes and needs to be renewed.

A research team from TU Wien [Vienna University of Technology] and the Università Politecnica delle Marche (Italy) has now succeeded in developing special titanium oxide nanoparticles that can be added to ordinary, commercially available wall paint to establish self-cleaning power: The nanoparticles are photocatalytically active, they can use sunlight not only to bind substances from the air, but also to decompose them afterwards. The wall makes the air cleaner — and cleans itself at the same time. Waste was used as the raw material for the new wall paint: metal scrap, which would otherwise have to be discarded, and dried fallen leaves.

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A March 25, 2024 Vienna University of Technology press release (also on EurekAlert), which originated the news item, describes the proposed technology,

Modified titanium oxide in the wall paint

A wide variety of pollutants occur in indoor air – from residues of cleaning agents and hygiene products to molecules that are produced during cooking or that are emitted by materials such as leather. In some cases, this can lead to health issues, which is then referred to as “sick building syndrome”.

“For years, people have been trying to use customized wall paints to clean the air,” says Prof. Günther Rupprechter from the Institute of Materials Chemistry at TU Wien. “Titanium oxide nanoparticles are particularly interesting in this context. They can bind and break down a wide range of pollutants.”

However, simply adding ordinary titanium oxide nanoparticles to the paint will affect the durability of the paint: just as pollutants are degraded by the nanoparticles, they can also make the paint itself unstable and create cracks. In the worst case, volatile organic compounds can even be released, which in turn can be harmful to health. After a certain time, the paint layer becomes gray and tinted, finally it has to be renewed.

Self-cleaning by light

However, the nanoparticles can clean themselves if they are irradiated with UV light. Titanium oxide is a so-called photocatalyst – a material that enables chemical reactions when exposed to suitable light. The UV radiation creates free charge carriers in the particles, which induce decomposition of the trapped pollutants from air into small parts and their release. In this way, the pollutants are rendered harmless, but do not remain permanently attached to the wall paint. The wall colour remains stable in the long term.

In practice, however, this is of little use – after all, it would be tedious to repeatedly irradiate the wall with intense UV light in order to drive the self-cleaning process. “Our goal was therefore to modify these particles in such a way that the photocatalytic effect can also be induced by ordinary sunlight,” explains Günther Rupprechter.

This is achieved by adding certain additional atoms to the titanium oxide nanoparticles, such as phosphorus, nitrogen, and carbon. As a result, the light frequencies that can be harvested by the particles change, and instead of just UV light, photocatalysis is then also triggered by ordinary visible light.

96% pollutant removal

“We have now investigated this phenomenon in great detail using a variety of different surface and nanoparticle analysis methods,” says Qaisar Maqbool, the first author of the study. “In this way, we were able to show exactly how these particles behave, before and after they were added to the wall paint.”

The research team mixed the modified titanium oxide nanoparticles with ordinary, commercially available wall paint and rinsed a painted surface with a solution containing pollutants. Subsequently, 96% of the pollutants could be degraded by natural sunlight. The colour itself does not change – because the pollutants are not only bound, but also broken down with the help of sunlight.

Waste as a raw material

For the commercial success of such paints, it is also important to avoid expensive raw materials . “In catalysis, for example, precious metals such as platinum or gold are used. In our case, however, elements that are readily available from everywhere are sufficient: To obtain phosphorus, nitrogen and carbon, we have used dried fallen leaves from olive trees, and the titanium for the titanium oxide nanoparticles was obtained from metal waste, which is normally simply thrown away,” says Günther Rupprechter.

This new type of wall paint combines several advantages at the same time: it removes pollutants from the air, it lasts longer than other paints – and it is even more resource-saving in production as it can be obtained from recycled materials. Further experiments are being carried out, and commercialisation of the wall paint is intended.

Here’s a link to and a citation for the paper,

Highly Stable Self-Cleaning Paints Based on Waste-Valorized PNC-Doped TiO2 Nanoparticles by Qaisar Maqbool, Orlando Favoni, Thomas Wicht, Niusha Lasemi, Simona Sabbatini, Michael Stöger-Pollach, Maria Letizia Ruello, Francesca Tittarelli, and Günther Rupprechter. ACS Catal. 2024, 14, 7, 4820–4834 DOI: https://doi.org/10.1021/acscatal.3c06203 Publication Date:March 15, 2024 Copyright © 2024 The Authors. Published by American Chemical Society. This publication is licensed under
CC-BY 4.0..

This paper is open access.

Probing the physical limits of plasmons in organic molecules with fewer than 50 atoms

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A Sept. 5, 2018  news item on ScienceDaily introduces the work,

Rice University [Texas, US] researchers are probing the physical limits of excited electronic states called plasmons by studying them in organic molecules with fewer than 50 atoms.

A Sept. 4, 2018 Rice University news release (also on EurekAlert published on Sept. 5, 2018), which originated the news item, explains what plasmons are and why this research is being undertaken,

Plasmons are oscillations in the plasma of free electrons that constantly swirl across the surface of conductive materials like metals. In some nanomaterials, a specific color of light can resonate with the plasma and cause the electrons inside it to lose their individual identities and move as one, in rhythmic waves. Rice’s Laboratory for Nanophotonics (LANP) has pioneered a growing list of plasmonic technologies for applications as diverse as color-changing glass, molecular sensing, cancer diagnosis and treatment, optoelectronics, solar energy collection and photocatalysis.

Reporting online in the Proceedings of the National Academy of Sciences, LANP scientists detailed the results of a two-year experimental and theoretical study of plasmons in three different polycyclic aromatic hydrocarbons (PAHs). Unlike the plasmons in relatively large metal nanoparticles, which can typically be described with classical electromagnetic theory like Maxwell’s [James Clerk Maxwell] equations, the paucity of atoms in the PAHs produces plasmons that can only be understood in terms of quantum mechanics, said study co-author and co-designer Naomi Halas, the director of LANP and the lead researcher on the project.

“These PAHs are essentially scraps of graphene that contain five or six fused benzene rings surrounded by a perimeter of hydrogen atoms,” Halas said. “There are so few atoms in each that adding or removing even a single electron dramatically changes their electronic behavior.”

Halas’ team had experimentally verified the existence of molecular plasmons in several previous studies. But an investigation that combined side by side theoretical and experimental perspectives was needed, said study co-author Luca Bursi, a postdoctoral research associate and theoretical physicist in the research group of study co-designer and co-author Peter Nordlander.

“Molecular excitations are a ubiquity in nature and very well studied, especially for neutral PAHs, which have been considered as the standard of non-plasmonic excitations in the past,” Bursi said. “Given how much is already known about PAHs, they were an ideal choice for further investigation of the properties of plasmonic excitations in systems as small as actual molecules, which represent a frontier of plasmonics.”

Lead co-author Kyle Chapkin, a Ph.D. student in applied physics in the Halas research group, said, “Molecular plasmonics is a new area at the interface between plasmonics and molecular chemistry, which is rapidly evolving. When plasmonics reach the molecular scale, we lose any sharp distinction of what constitutes a plasmon and what doesn’t. We need to find a new rationale to explain this regime, which was one of the main motivations for this study.”

In their native state, the PAHs that were studied — anthanthrene, benzo[ghi]perylene and perylene — are charge-neutral and cannot be excited into a plasmonic state by the visible wavelengths of light used in Chapkin’s experiments. In their anionic form, the molecules contain an additional electron, which alters their “ground state” and makes them plasmonically active in the visible spectrum. By exciting both the native and anionic forms of the molecules and comparing precisely how they behaved as they relaxed back to their ground states, Chapkin and Bursi built a solid case that the anionic forms do support molecular plasmons in the visible spectrum.

The key, Chapkin said, was identifying a number of similarities between the behavior of known plasmonic particles and the anionic PAHs. By matching both the timescales and modes for relaxation behaviors, the LANP team built up a picture of a characteristic dynamics of low-energy plasmonic excitations in the anionic PAHs.

“In molecules, all excitations are molecular excitations, but select excited states show some characteristics that allow us to draw a parallel with the well-established plasmonic excitations in metal nanostructures,” Bursi said.

“This study offers a window on the sometimes surprising behavior of collective excitations in few-atom quantum systems,” Halas said. “What we’ve learned here will aid our lab and others in developing quantum-plasmonic approaches for ultrafast color-changing glass, molecular-scale optoelectronics and nonlinear plasmon-mediated optics.”

Here’s a link to and a citation for the paper,

Lifetime dynamics of plasmons in the few-atom limit by Kyle D. Chapkin, Luca Bursi, Grant J. Stec, Adam Lauchner, Nathaniel J. Hogan, Yao Cui, Peter Nordlander, and Naomi J. Halas. PNAS September 11, 2018 115 (37) 9134-9139; published ahead of print August 27, 2018 DOI: https://doi.org/10.1073/pnas.1805357115

This paper is behind a paywall.

Generating power from polluted air

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I have no idea how viable this concept might be but it is certainly appealing, From a May 8, 2017 news item on Nanowerk (Note: A link has been removed),

Researchers from the University of Antwerp and KU Leuven (University of Leuven), Belgium, have succeeded in developing a process that purifies air and, at the same time, generates power. The device must only be exposed to light in order to function (ChemSusChem, “Harvesting Hydrogen Gas from Air Pollutants with an Unbiased Gas Phase Photoelectrochemical Cell”).

Caption: The new device must only be exposed to light in order to purify air and generate power. Credit: UAntwerpen and KU Leuven

A May 8, 2017 University of Leuven press release (also on EurekAlert), which originated the news item, describes this nifty research in slightly more detail,

“We use a small device with two rooms separated by a membrane,” explains Professor Sammy Verbruggen (UAntwerp/KU Leuven). “Air is purified on one side, while on the other side hydrogen gas is produced from a part of the degradation products. This hydrogen gas can be stored and used later as fuel, as is already being done in some hydrogen buses, for example.”

In this way, the researchers respond to two major social needs: clean air and alternative energy production. The heart of the solution lies at the membrane level, where the researchers use specific nanomaterials. “These catalysts are capable of producing hydrogen gas and breaking down air pollution,” explains Professor Verbruggen. “In the past, these cells were mostly used to extract hydrogen from water. We have now discovered that this is also possible, and even more efficient, with polluted air.”

It seems to be a complex process, but it is not: the device must only be exposed to light. The researchers’ goal is to be able to use sunlight, as the processes underlying the technology are similar to those found in solar panels. The difference here is that electricity is not generated directly, but rather that air is purified while the generated power is stored as hydrogen gas.

“We are currently working on a scale of only a few square centimetres. At a later stage, we would like to scale up our technology to make the process industrially applicable. We are also working on improving our materials so we can use sunlight more efficiently to trigger the reactions. “

Here’s a link to and a citation for the paper,

Harvesting Hydrogen Gas from Air Pollutants with an Unbiased Gas Phase Photoelectrochemical Cell. by  Prof. Dr. Sammy W. Verbruggen, Myrthe Van Hal1, Tom Bosserez, Dr. Jan Rongé, Dr. Birger Hauchecorne, Prof. Dr. Johan A. Martens, and Prof. Dr. Silvia Lenaerts. ChemSusChem Volume 10, Issue 7, pages 1413–1418, April 10, 2017 DOI: 10.1002/cssc.201601806 Version of Record online: 6 MAR 2017

© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

New photocatalytic approach to cleaning wastewater from oil sands

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With oil sands in the title, this story had to mention the Canadian province of Alberta, which has been widely castigated and applauded for its oil extraction efforts in their massive oil sands field. A Nov. 24, 2015 news item on Nanotechnology Now describes a new technology for cleaning the wastewater from oil sands extraction processes,

Researchers have developed a process to remove contaminants from oil sands wastewater using only sunlight and nanoparticles that is more effective and inexpensive than conventional treatment methods.

Frank Gu, a professor in the Faculty of Engineering at the University of Waterloo [in the province of Ontario] and Canada Research Chair in Nanotechnology Engineering, is the senior researcher on the team that was the first to find that photocatalysis — a chemical reaction that involves the absorption of light by nanoparticles — can completely eliminate naphthenic acids in oil sands wastewater, and within hours. Naphthenic acids pose a threat to ecology and human health. Water in tailing ponds left to biodegrade naturally in the environment still contains these contaminants decades later.

A Nov. 23, 2015 University of Waterloo news release, which originated the news item, expands on the theme but doesn’t provide much in the way of technical detail,

“With about a billion tonnes of water stored in ponds in Alberta, removing naphthenic acids is one of the largest environmental challenges in Canada,” said Tim Leshuk, a PhD candidate in chemical engineering at Waterloo. He is the lead author of this paper and a recipient of the prestigious Vanier Canada Graduate Scholarship. “Conventional treatments people have tried either haven’t worked, or if they have worked, they’ve been far too impractical or expensive to solve the size of the problem.  Waterloo’s technology is the first step of what looks like a very practical and green treatment method.”

Unlike treating polluted water with chlorine or membrane filtering, the Waterloo technology is energy-efficient and relatively inexpensive. Nanoparticles become extremely reactive when exposed to sunlight and break down the persistent pollutants in their individual atoms, completely removing them from the water. This treatment depends on only sunlight for energy, and the nanoparticles can be recovered and reused indefinitely.

Next steps for the Waterloo research include ensuring that the treated water meets all of the objectives Canadian environmental legislation and regulations required to ensure it can be safely discharged from sources larger than the samples, such as tailing ponds.

Here’s a link to and a citation for the paper,

Solar photocatalytic degradation of naphthenic acids in oil sands process-affected water by Tim Leshuk, Timothy Wong, Stuart Linley, Kerry M. Peru, John V. Headley, Frank Gu. Chemosphere Volume 144, February 2016, Pages 1854–1861 doi:10.1016/j.chemosphere.2015.10.073

This paper is behind a paywall.

Astonishing observation about gold nanoparticles and self-assembly

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An Aug. 4, 2014 news item on ScienceDaily features research on self-assembling gold nanoparticles from Helmholtz-Zentrum Berlin für Materialien und Energie (HZB) and Humboldt-Universität zu Berlin (HU, Berlin),

Researchers at HZB in co-operation with Humboldt-Universität zu Berlin (HU, Berlin) have made an astonishing observation: they were investigating the formation of gold nanoparticles in a solvent and observed that the nanoparticles had not distributed themselves uniformly, but instead were self-assembled into small clusters.

An Aug. 4, 2014 HZB press release (also on EurekAlert), which originated the news item, provides additional technical information about the equipment used to make the observations,

This was determined using Small-Angle X-ray Scattering (SAXS) at BESSY II. A thorough examination with an [a transmission] electron microscope (TEM) confirmed their result. “The research on this phenomenon is now proceeding because we are convinced that such nanoclusters lend themselves as catalysts, whether in fuel cells, in photocatalytic water splitting, or for other important reactions in chemical engineering”, explains Dr. Armin Hoell of HZB. The results have just appeared in two peer reviewed international academic journals.

“What is special about the new process is that it is extremely simple and works with an environmentally friendly and inexpensive solvent”, explains Professor Klaus Rademann from HU Berlin. The solvent actually consists of two powders that one would sooner expect to find in agriculture that in a research laboratory: a supplement in chicken feed (choline chloride, aka vitamin B), and urea. British colleagues discovered a few years ago that mixing the two powders forms a transparent liquid able to dissolve metal oxides and heavy metals, called deep eutectic solvent (DES). The researchers in Berlin then positioned above the solvent gold foil that they could bombard with ions of noble gas in order to detach individual atoms of gold. This is how nanoparticles initially formed that distributed themselves in the solvent.

The researchers did not expect what happened next (from the press release),

The longer the bombardment (sputtering) of the gold foil lasted, the larger the nanoparticles could become, the scientists reasoned. However, this was not the case: the particles ceased growing at five nanometres. Instead, an increasing number of nanoparticles formed over longer sputtering times. The second surprise: these nanoparticles did not distribute themselves uniformly in the liquid, but instead self-assembled into small groups or clusters that could consist of up to twelve nanoparticles.

These kinds of observations cannot be easily made under a microscope, of course, but require instead an indirect, statistical approach: “Using small-angle X-ray scattering at BESSY II, we were not only able to ascertain that the nanoparticles are all around five nanometres in diameter, but also measure what the separations between them are. From these measurements, we found the nanoparticles arrange themselves into clusters”, explains Hoell.

…

“We ran computer models in advance of how the nanoparticles could distribute themselves in the solution to better understand the measurement results, and then compared the results of the simulation with the results of the small-angle X-ray scattering”, explains Dr. Vikram Singh Raghuwanshi, who works as a postdoc at HU Berlin as well as HZB. An image from the cryogenic transmission electron microscope that colleagues at HU prepared confirmed their findings. “But we could not have achieved this result using only electron microscopy, since it can only display details and sections of the specimen”, Hoell emphasised. “Small-angle X-ray scattering is indispensable for measuring general trends and averages!”

The press release concludes thusly,

It is obvious to the researchers that the special DES-solvent plays an important role in this self-organising process: various interactions between the ions of the solvent and the particles of gold result firstly in the nanoparticles reaching only a few thousand atoms in size, and secondly that they mutually attract somewhat – but only weakly – so that the small clusters arise. “We know, however, that these kinds of small clusters of nanoparticles are especially effective as catalysts for chemical reactions we want: a many-fold increase in the reaction speed due only to particle arrangement has already been demonstrated”, says Rademann.

Here are links to and citations for the two papers the team has published on their latest work,

Deep Eutectic Solvents for the Self-Assembly of Gold Nanoparticles: A SAXS, UV–Vis, and TEM Investigation by Vikram Singh Raghuwanshi, Miguel Ochmann, Armin Hoell, Frank Polzer, and Klaus Rademann. Langmuir, 2014, 30 (21), pp 6038–6046 DOI: 10.1021/la500979p Publication Date (Web): May 11, 2014

Copyright © 2014 American Chemical Society

Self-assembly of gold nanoparticles on deep eutectic solvent (DES) surfaces by V. S. Raghuwanshi, M. Ochmann, F. Polzer, A. Hoell and K. Rademann.  Chem. Commun., 2014,50, 8693-8696 DOI: 10.1039/C4CC02588A
First published online 10 Jun 2014

Both papers are behind a paywall.

This research is being presented at two conferences, one of which is taking place now (Aug.5, 2014; from the press release),

Dr. Raghuwanshi will give a talk on these results, as well as providing a preview of the catalysis research approaches now planned, at the International conference, IUCr2014, taking place from 5-12 August 2014 in Montreal, Canada.

In the coming year, HZB will incidentally be one of the hosts of the 16th International Small-Angle Scattering Conference, SAS2015.

There you have all the news.

Laundry detergents that clean clothes and pollution from the air

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Tony Ryan, as an individual (and with Helen Storey), knows how to provoke interest in a topic many of us find tired, air pollution. This time, Ryan and Storey have developed a laundry detergent additive through their Catalytic Clothing venture (mentioned previously in a Feb. 24, 2012 posting and in a July 8, 2011 posting). From Adele Peters’ July 22, 2014 article for Fast Company (Note: A link has been removed),

Here’s another reason cities need more pedestrians: If someone is wearing clothes that happened to be washed in the right detergent, just their walking down the street can suck smog out of the surrounding air.

For the last few years, researchers at the Catalytic Clothing project have been testing a pollution-fighting laundry detergent that coats clothing in nano-sized particles of titanium dioxide. The additive traps smog and converts it into a harmless byproduct. It’s the same principle that has been used smog-eating buildings and roads, but clothing has the advantage of actually taking up more space.

Kasey Lum in a June 25, 2014 article for Ecouterre describes the product as a “laundry additive [which] could turn clothing in mobile air purifiers,”

CatClo piggybacks the regular laundering process to deposit nanoparticles of titanium dioxide onto the fibers of the clothing. Exposure to light excites electrons on the particles’ surface, creating free radicals that react with water to make hydrogen peroxide. This, in turn, “bleaches out” volatile organic compounds and nitrogen oxides in the atmosphere, according to Storey, rendering them harmless.

Lum referenced a May 23, 2014 article written by Helen Storey and Tony Ryan for the UK’s Guardian, newspaper which gives a history of their venture, Catalytic Clothing, and an update on their laundry additive (Note: Links have been removed),

It was through a weird and wonderful coincidence on BBC [British Broadcasting Corporation] Radio 4 that we met to discuss quantum mechanics and plastic packaging, resulting in the Wonderland Project, where we created disappearing gowns and bottles as a metaphor for a planet that is going the same way.

Spurred by this collaborative way of working, Wonderland led to Catalytic Clothing, a liquid laundry additive. The idea came out of conversations about how we could harness the surface of our clothing and the power of fashion to communicate complex scientific ideas – and so began the campaign for clean air.

(When I first wrote about Catalytic Clothing I was under the impression that it was an art/science venture focused on clothing as a means of cleaning the air. I was unaware they were working on a laundry additive.)

Getting back to Storey’s and Ryan’s article (Note: A link has been removed),

Catalytic Clothing (CatClo) uses existing technology in a radical new way. Photocatalytic surface treatments that break down airborne pollutants are widely applied to urban spaces, in concrete, on buildings and self-cleaning glass. The efficacy is greatly increased when applied to clothing – not only is there a large surface area, but there is also a temperature gradient creating a constant flux of air, and movement through walking creates our own micro-wind, so catalysing ourselves makes us the most effective air purifiers of them all.

CatClo contains nanoparticles of titania (TiO2) a thousand times finer than a human hair. [generally nanoscale is described as between 1/60,000 to 1/100,000 of a hair’s width] When clothes are laundered through the washing process, particles are deposited onto the fibres of the fabric. When the catalysed clothes are worn, light shines on the titanium particles and it excites the electrons on the particle surface. These electrons cause oxygen molecules to split creating free-radicals that then react with water to make hydrogen peroxide. This then bleaches out the volatile organic compounds and nitrogen oxides (NOx) that are polluting the atmosphere.

The whole process is sped up when people, wearing the clothes, are walking down the street. The collective power of everyone wearing clothes treated with CatClo is extraordinary. If the whole population of a city such as Sheffield was to launder their clothes at home with a product containing CatClo technology they would have the power to remove three tonnes per day of harmful NOx pollution.

So, if the technology exists to clear the air, why isn’t it available? From Storey’s and Ryan’s article,

Altruism, is a hard concept to sell to big business. We have approached and worked with some of the world’s largest producers of laundry products but even though the technology exists and could be relatively cheap to add to existing products, it’s proved to be a tough sell. The fact that by catalysing your clothes the clean air you create will be breathed in by the person behind you is not seen as marketable.

A more serious issue is that photocatalysts can’t tell the difference between a bad pollutant and a “good” one; for example, it treats perfume as just another volatile organic compound like pollution. This is an untenable threat to an entire industry and existing products owned by those best able to take CatClo to market.

We’ve recently travelled to China to see whether CatClo could work there. China is a place where perfume isn’t culturally valued, but the common good is, so a country with one of the biggest pollution problems on the planet, and a government that isn’t hidebound by business as usual, might be the best place to start.

In the midst of developing their laundry additive, Storey and Ryan produced a pop-up exhibition, A Field of Jeans (first mentioned here in an Oct. 13, 2011 posting which lists events for the 2011 London Science Festival), to raise public awareness and support (from the article),

During the research period, we realised that there were more jeans on the planet than people. Knowing this, we launched a pop-up exhibition, A Field of Jeans. The jeans we catalysed are all recycled and as it turns out, because of the special nature of cotton denim, are the most efficacious fabric of all to support the catalysts.

The public have been overwhelmingly supportive; once fears about the “chemicals”, “nanotech” or becoming dirt magnets were dispelled, we captured people’s imagination and proved that CatClo could eventually be as normal as fluoride in toothpaste with enormous potential to increase wellbeing and clean up our polluted cities.

The pop-up exhibition is now at Thomas Tallis School in London (from the Catalytic Clothing homepage),

New 2013/2014
Field of Jeans is at Thomas Tallis school from December 2nd 2013 until further notice. Jeans can be viewed from Kidbrooke Park Road, London SE3 outside the main school entrance. This will inspire a piece of work across the school called Catalytic Learning. More will be posted here soon.
Click here for images
http://www.thomastallis.co.uk/

Here’s an image from the Field of Jeans,

Image can be found here at: https://www.flickr.com/photos/helenstoreyfoundation/sets/72157638346745735/

Image can be found here at: https://www.flickr.com/photos/helenstoreyfoundation/sets/72157638346745735/

I last featured Tony Ryan’s work here in a May 15, 2014 posting about a poem and a catalytic billboard at the University of Sheffield where Ryan is the Pro-Vice-Chancellor for Science.

Materials research and nanotechnology for clean energy at Addis Ababa University (Ethiopia)

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Getting to the bottom line of a complex set of  interlinked programs and initiatives, it’s safe to say that a group of US students went to study with research Addis Ababa University (Ethiopia) in the first Materials Research School which was held Dec. 9 -21, 2012.

Rutgers University (New Jersey, US)  student Aleksandra Biedron attended the Materials Research School as a member of a joint Rutgers University-Princeton University Nanotechnology for Clean Energy graduate training program (one of the US National Science Foundation’s Integrative Graduate Education Research Traineeship [IGERT] programs).

In a Summer 2013 (volume 14) issue of Rutgers University’s Chemistry and Chemical Biology News, Biedron describes the experience,

The program brought together approximately 50 graduate students and early-career materials researchers from across the United States and East Africa, as well as 15 internationally recognized instructors, for two weeks of lectures, problem solving, and cultural exchange. “I was interested in meeting young African scientists to discuss energy materials, a universal concern, which is relevant to my research in ionic liquids,” said Biedron, a graduate of Livingston High School [Berkeley Heights, New Jersey]. “I was also excited to see Addis Ababa, Ethiopia, and experience the culture and historical attractions.”

A cornerstone of the Nanotechnology for Clean Energy IGERT program is having the students apply their training in a dynamic educational exchange program with African institutions, promoting development of the students’ global awareness and understanding of the challenges involved in global scientific and economic development. In Addis Ababa, Biedron quickly noticed how different the scope of research was between the African scientists and their international counterparts.

“The African scientists’ research was really solution-based,” said Biedron. “They were looking at how they could use their natural resources to solve some of their region’s most pressing issues, not only for energy, but also health, clean water, and housing. You don’t really see that as much in the U.S. because we are already thinking about the future, 10 or 20 years from now.”

H/T centraljerseycentral.com, Aug. 1, 2013 news item.

I found a little more information about the first Materials Research School on this Columbia University JUAMI (Joint US-Africa Materials Initiative) webpage,

The Joint US-Africa Materials Initiative
Announces its first Materials Research School
To be held in Addis Ababa, Ethiopia, December 9-21, 2012

Theme of the school:

The first school will concentrate on materials research for sustainable energy. Tutorials and seminar topics will range from photocatalysis and photovoltaics to fuel cells and batteries.

Goals of the school:

The initiative aims to build materials science research and collaborations between the United States and Africa, with an initial focus on East Africa, and to develop ties between young materials researchers in both regions in a school taught by top materials researchers. The school will bring together approximately 50 PhD and early career materials researchers from across the US and East Africa, and 15 internationally recognized instructors, for two weeks of lectures, problem solving and cultural exchange in historic Addis Ababa, Ethiopia. Topics include photocatalysis, photovoltaics, thermoelectrics, fuel cells, and batteries.

I also found this on the IGERT homepage,

IGERT Trainees participate in:
  • Interdisciplinary courses in the fundamentals of energy technology, nanotechnology and energy policy.
  • Dissertation research emphasizing nanotechnology and energy.
  • Dynamic educational exchange between U.S. and select African institutions.