WE CLEAN THE AIR WE BREATHE
WITH PHOTOCATALYTIC SURFACES
THE PROCESS OF PHOTOCATALYST ACTION
The process of photocatalytic action is initiated when the Titanium dioxide (𝑇𝑖𝑂2) applied to a surface absorbs UV light, once this occurs, Hydroxide (OH*) is produced which acts as a strong oxidizing agent. The Hydroxide will then surround and destroy the dangerous air pollutants and organics: Nitrogen Oxides (𝑁𝑂 𝑎𝑛𝑑 𝑁𝑂2=𝑁𝑂𝑥 ), VOCs (such as formaldehyde and benzene), other organics (such as E.coli., S.aureus, K.pneumonia, algaes and more). These harmful pollutants and bacterias are then disintegrated and turned into nitrate (𝑁𝑂3−) together with some steam (H2O) and carbon dioxide (CO2) which is released to the atmosphere. The proprietary solution and application method designed and developed by Photocat allows for a highly effective degradation process through a transparent application. The transparency is an important aspect of Photocat’s innovation because it allows more surface materials to become photocatalytic without any cosmetic disadvantages. An innovation we believe marks a shift in the commercialization of this technology.
Photocatalytic technology is well documented and had a tremendous commercial breakthrough during the 90’s and in the beginning of this century. The documentation of performance is very strong and supported by ISO (International Organization for Standards) and EN (European Standards) standard tests, as well as being certified by TCNA (The Tile Council of North America) for showing real effect with reducing NOx and reducing the growth of microorganisms.
The photocatalytic mechanism was first discovered in 1972 by Prof. A. Fujishima and Prof. K. Honda from the University of Tokyo (A. Fujishima and K. Honda, Nature, Vol 238, p 37-38, July 7th 1972). They were the first to successfully split water molecules by photo electrochemical decomposition of water under irradiation with light and without any applied electric power using a photo catalyst and sun light. However, it was not until a research group under Prof. A. Fujishima discovered the direct self-cleaning effect of the photo catalytic technology in the 1990’s that the technology became commercial (R. Wang, K. Hashimoto, A. Fujishima et al., Nature Vol 338, p 431-432, July 31st 1997). Today, the photo catalytic technology has become a mature market technology and the market for photo catalytic products is a billion-dollar industry in Japan as well as abroad, with more than a 100 million square meters installed per year. In 2012, Prof. K. Hashimoto from the University of Tokyo was one of the nominees for the prestigious Nobel Prize in Chemistry. But already in 2004 the prestigious Japan Prize was given to Prof. K. Honda and Prof. A. Fujishima for their discovery of water splitting by photo catalysis, the so called “Honda-Fujishima effect” named after the two inventors. Thus, they pioneered research on artificial photosynthesis and production of hydrogen as a clean energy from water by using solar light. Furthermore, the development of the self-cleaning coating of TiO2 on a variety of surfaces is now creating a new industry of photo catalysts, which significantly contributes to the environmental conservation.
Extensive research- and on site project tests and evaluations have been conducted over the last decade in several countries including: The Netherlands (Castorweg – Hengelo 2008-2011), The Netherlands (Airport Schipol 2009-2010), The UK (London – High Holborn 2007-2010) and Sweden (Malmø – Admiralsgaten 2009-2010). The activities have been initiated by research institutions, city authorities and commercial companies and in most cases a combination of all. The European Union has sponsored several projects and some are still running. Furthermore, a case study on the Maastunnel in Rotterdam in the Netherlands was presented in the (European Coating Journal in 2012). It is worth remarking that this study shows that, without taking the societal Health Expenses into account, there is a payback time of only 4 years.
In 2016 the European Union published a report assessing the effect of photocatalytic concrete in regards to degrading air pollution. The report presents three cases, two of which are in Denmark, and one in Spain. Testing the technology in various places, adhering to different climates, is important in characterizing the effect which naturally is higher in southern European countries due to their higher degree of sun light. The results of the three test sites were incredible strong, and the report writes:
“It is therefore clear that the high selectivity of the Light2CAT photocatalyst can really turn into a major benefit for air quality by directly lowering the amount of NO2 in the air and indirectly by reducing the amount of ozone produced by NO2 photolysis (and followed reaction with molecular oxygen).”
The report found that the reduction in NOx ranged from 5% to 56.5% with the strongest results found in Spain. Furthermore, the test period was done in two stages (March to April and July to August). The results are of course highly affected by the time of testing and by location. The best performance in Denmark was an 18.9% reduction in NOx. The test site in Spain, Valencia, showed even more remarkable results, clearly showing the potential for this technology, reducing NO by 38.6 ppb and NO2 by 8.8 ppb (a reduction of 72.7% and 28.4% respectively), reflecting a total reduction of 56.5%.
OUR TECHNOLOGY PLATFORM
Photocat’s products are top performers within their category representing some of the highest efficiency seen both in laboratory tests and in real life. The ISO 22197-1 results concludes that the efficiency is far above what is perceived excellent, both by internal and external 3rd party tests by the renowned D-Tox laboratory in Hannover. Photocat’s product are well documentet and validatet: “The Photocat (bitumen) product belongs to the group of top products tested in this lab” D-Tox laboratory.
Numerous studies are showing the degradation power of photo catalytic products and the benefits for normal consumers. The common conclusion, which is well adapted, is that this technology is very potent to solve air quality problems by reducing the harmful NOx and VOCs using photo catalyst and light. The technology behind the Photocat products has been documented by various EN and ISO standards as well as been certified by the TCNA. The Photocat technology was tested in a Round-Robin test between two university labs, an industrial lab and the Photocat lab. From this study the head of the Round-Robin test, Prof. Bahnemann from the University of Leibniz, who is the leading professor in testing photo catalytic products in Europe and who adapted the Japanese photo catalytic JIS standards and transferred them to the European ISO standards, concluded that: “The variance between values from Photocat measurement and Leibniz measurement is absolutely acceptable and considered similar”
Meaning that, Prof. Bahnemann achieved the same results from his tests of the Photocat technologies as the results presented by the company itself. Until this date Photocat has performed more than 2.500, ISO 22197-1 NOx degradation tests, both in its own lab and through third party institutions, all validating the effects of Photocat’s technology. The Photocat technology is also tested through TCNA according to ISO 27447:2009(E) which is the test method for antibacterial activity of semiconducting photocatalytic materials. The conclusion of these tests was that the tested floor with photo catalytic technology exhibited a reduction of 99.65% of the tested E. coli, 99.63% of the tested S. aureus and 99.7% of the tested K.pneumoniae. The results for the tested Photocat product were all calculated with respect to a base reference without catalytic effect.
The Photocat technology is, as far as known, the most tested technology regarding real life tests. The Photocat technology has been tested in a 2-year demonstration case at the Copenhagen airport, where it was documented that the NOxOFF™ technology could reduce the average NOx concentration with 13% overall. Furthermore, it was documented that in peak hours (both regarding to sun light and NOx concentration) the effectiveness was up to a 24% reduction in NOx levels.
Photocat recently finalized a three year study which will be published in 2018. The study found that the photocatalytic technology is both a tangible and economic cost-effective instrument to clean the air in cities with a life-sustaining NOxOFF treatment of 5,000 m2 in the parking lots of Skt. Peder-/Skt. Ols Stræde and Bønnelyckes Plads in the Municipality of Roskilde in Denmark. An optimized photocatalytic treatment to the asphalt surface in Roskilde was developed for the project. At the same time an in-situ set-up was developed enabling to test the activity of the photocatalytic treatment in the test period of three years. Based on the test result it was concluded that the photocatalytic NOxOFF treatment is stable over time and that the NOxOFF technology delivers an internal rate of return higher than 20 % and is a highly cost effective method of improving air quality in cities.
Photocat holds the right to commercially exploit 36 approved patents and 56 pending patents worldwide that protects the NOxOFF™ and actiFLOOR™ technology and application method. The technology is today available across three surface materials in Europe and North America. To date, the technology is deployed across more than 1 million square meters which on a daily basis removes 30.9 kg/NOx from the air we breathe.
actiFLOOR is a treatment that can be applied to any flooring surface. The Titanium dioxide in the treatment naturally reacts to the presence of natural or artificial light. When exposed to light the surface acts as a giant natural filter. As toxic molecules come in contact with the active surface, they are naturally broken down and converted into water and carbon dioxide.
NOxOFF is a treatment on concrete, pavers and bitumen surfaces. When the sunlight hits the treated surface, the NOxOFF is activated. NOx from the air is then captured, and the sunlight is used to degrade the captured NOx via photocatalysis to nitrate. The nitrate is then washed away with rain or periodic rinsing, resulting in cleaned air.
Photocat Garden is a surface after treatment of outdoor concrete. The product’s unique and “active” surface secures an environmental concrete surface. The product is not only an impregnation but also has effect in relation to degradation of NOx.
ShineOn™ offers documented ability to make vertical glass surfaces self-cleaning. The solution is the first in the world to offer this documented effect for the aftermarket. Photocat offers this product to select applicators and delivers education, brand material, pricing calculations and the catalyst materials. The solution has been documented to remove more than 85 percent of dirt, which is in full compliance with self-cleaning standards. Documented by the Danish Technical Institute.
Fujishima, A., Rao, N. T., & Tryk, A. D. (2000) Titanium dioxide photocatalysis. Journal of Photochemistry and Photobiology C: Photochemistry Reviews 1 (2000) 1-21.
Fujishima, A., Zhang, X., & Tryk, A. D. (2008) TiO2 photocatalysis and related surface phenomena. Surface Science Reports 63 (2008) 515-582.
Folli, A., Strøm, M., Madsen, T.P., Henriksen, T., Lang, J., Emenius, J., Kleve-brant, T., Nilsson, Å (2015): Field study of air purifying paving elements containing TiO2. Atmospheric Environment 107 (2015) 44-51.
Poulsen, S. L., Svec, O. M., & Folli, A. (2016). Assessment of the air quality after the execution of the photocatalytic structures. FP7-ENV-2011-ECO-INNO-TwoStage-283062-Light2CAT-DL-DTI-D5.3. 10.03.2016.