BOCHUM, Germany – Only light, aerial oxygen and a catalyst are needed to remove pollutants from water. Researchers from Ruhr-University Bochum (RUB), Bochum, Germany, are collaborating with colleagues from seven different countries in order to develop a photocatalyst that is efficient enough to be profitable. Led by Professor Radim Beránek of Ruhr-University Bochum, the scientists are combining sunlight-absorbing semiconductors and nanostructured materials, which they optimize for electron transfer processes. The aim is to implement the newly developed photocatalysts into a liquid paint with which photoreactors can easily be coated. The EU is supporting the project within its 7th Framework Program (FP7) with EUR 3.7 million funding for three years.

People from many countries of the world extensively use pesticides, which contaminate drinking and irrigation water with toxic organic compounds. In rural areas of Vietnam, herbicides and dioxins, resistant to degradation, made their way into the water cycle during the Vietnam War. Cancer and abnormalities in newborns can be the consequence. "Photocatalysis is potentially one of the cheapest and most efficient methods for purifying water from pollutants," Beránek says. Sunlight and oxygen establish oxidizing conditions under which toxins are easily degraded into non-harmful substances like water and carbon dioxide. Up to now, the process has faced two problems: degradation rates are too low and assembly of the needed photoreactors is too expensive.

Within the project, 4G-PHOTOCAT, researchers aim to develop cost-efficient photocatalysts with a considerably improved degradation rate. They are fabricating innovative composite materials consisting of semiconductors and nanostructured metal oxides. In order to achieve the optimal architecture for the product, they are using advanced chemical deposition techniques with a high degree of control over composition and morphology. "Our ultimate goal is to implement the newly developed photocatalysts into a liquid paint," Radim Beránek says. "Photoreactors painted with that liquid can be used, for example, for water decontamination in remote rural areas of Vietnam."

4G-PHOTOCAT is combining the expertise of seven academic and three industrial partners from five European countries and two Southeast Asian countries. At the RUB, Beránek is collaborating with Dr. Roland A. Fischer (Inorganic Chemistry II), Dr. Martin Muhler and Dr. Jennifer Strunk (Industrial Chemistry). The international collaborators include scientists from the University College London, J. Heyrovský Institute of Physical Chemistry in Prague, Jagiellonian University Krakow, University of Helsinki, Universiti Teknologi Malaysia and Hanoi University of Agriculture. Industrial partners from Finland (Picosun), Czech Republic (Advanced Materials) and Vietnam (Q&A) have joined the team.