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Physical chemistry, Analytical chemistry, Environmental sciences
Work in photochemistry work peaked in the 1980’s where there was the prospect of using sunlight shining on suspensions of titanium dioxide in order to catalytically cleave water into hydrogen and oxygen [1-5]. In this way a clean and efficient method of producing hydrogen as a fuel was envisaged. However, there was a requirement to use a rather high energy light to achieve the splitting and it was not as efficient with visible light. Doped TiO2 layers have been used in a three electrode system for formic acid degradation. In this work, the system uses an electrode coated with TiO2 to oxidise organic compounds, along with an air electrode as a cathode where oxygen reduction occurs. In this case the light source is a tungsten source which is readily available and safe in comparison with UV sources. This practical demonstrates that it is possible to directly degrade organics in wastewater, assisted with light, and will also generate a current. So there is an advantage from two fronts. One is the lowering of chemical oxygen demand, COD and the other is the yield of current which may be used for a purpose such as preventing corrosion in remote pipelines.
F.Touati, J.Cassidy, K.G.McGuigan, J.Chem. Ed. 84, (2007), 299-301. doi:10.1021/ed084p299