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Fig. 1 Current maps for a glassy carbon electrode (left panel) and epitaxial graphene (right panel) on Si-face 4H-SiC after exposure to Pb2+. Brighter regions correspond to a higher current density. The main difference between these two is that the graphene electrode exhibited a well-defined and higher stripping peak (brighter colour) at lower Pb2+ concentrations compared to the glassy carbon electrode

Science for safety

13/02/17

Scientists from Linköping University, Sweden, explain how science and business combine to make the world a safer place

Linköping University is an outstanding hi-tech centre located in Sweden’s south that creates new scientific fields and successfully bridges the gap between research and business. Its business-friendly environment fosters the dynamic growth of infrastructure and science vitality. Such favourable conditions promote new spin-off companies (for instance GraphenSiC AB) within the home region, which motivates the practical implementation of innovative scientific hypotheses.

GraphenSiC AB was founded by Professor Rositsa Yakimova and colleagues in 2011. The spin-off is now the manufacturing leader in epitaxial graphene technology and the preferred graphene brand for the ‘non-exfoliated’ graphene community worldwide. Focusing on sustainability and environmental problems, GraphenSiC fabricates ‘green’, highly sensitive material – monolayer epitaxial graphene on SiC – and helps the research group to implement it for the development of technologies for gas, biological and toxic metal sensors.

In line with the scientific and business strategies, the team strengthens the development of green sensing platforms based on epitaxial graphene for the real-time detection of hazardous heavy metal contaminants. The interest in this field is triggered by the global challenge related to the necessity of minimising the negative environmental impact of heavy metals contaminants.

The health benefits of graphene

Prompted by World Health Organization (WHO) reports on the toxicological effects of heavy metals and corresponding health risks, a designated team – including Dr Ivan Shtepliuk, Dr Volodymyr Khranovskyy, Dr Mikhail Vagin and Yakimova – is engaged in exploring the electrochemical activity of epitaxial graphene towards the recognition of cadmium (Cd), lead (Pb) and mercury (Hg) in aqueous solutions. Due to its high sensing ability, large surface area and excellent stripping behaviour, epitaxial graphene can interact with an increased number of heavy metal species and enhance the response signal compared with that of a glassy carbon electrode (GCE) – the most frequently used working electrode (Fig. 1) for lead ions.

Theoretical modelling of the heavy metal interaction with graphene is guiding the experimental approach: the graphene electrode exhibits a sharp current peak for the lead ions with an excellent detection limit of 2μg·L-1, while the WHO permissible limit is 10μg·L-1 in drinking water. Similar studies are ongoing for mercury and cadmium, as well as others.

The results indicate that graphene is a promising green material to be used as advanced working electrodes for rapid and reliable electrochemical detection of low concentrations of heavy metals in drinking water and vital biological liquids. The platform under development will also include Graphene-SiC Schottky diodes offering the possibility to read very small concentrations. The extraordinary Schottky barrier homogeneity over a large surface area opens an avenue for the realisation of integrated sensor arrays.

The team is developing a long-term strategy which includes sensing technology and addresses the safe removal of toxic metal species from drinking and waste water. Graphene derivatives like graphene oxide are, due to an enhanced chemical activity, regarded as efficient and cost-effective adsorbents, and were recently included in the portfolio of the functional materials produced and explored in the research group.

Rositsa Yakimova
Department of Physics, Chemistry and Biology (IFM)
Linköping University
+46 706772528
rositsa.yakimova@liu.se
http://www.ifm.liu.se/materialphysics/semicond

Contact Info
Author
Rositsa Yakimova
Organisation
Department of Physics, Chemistry and Biology (IFM), Linköping University
Telephone
+46 706772528
Department of Physics, Chemistry and Biology (IFM), Linköping University
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