Wireless Electronic Light Emission: An Introduction to Bipolar Electrochemistry

Abstract

Electrochemistry is taught in most undergraduate chemistry programs. Although this topic is important for students due to its broad interest in industry (energy, diagnostics, car industry, etc.), they often find it difficult, because it is based on a combination of various physical concepts such as electric fields, interfacial processes or charge and mass transport. Among electrochemical concepts, bipolar electrochemistry is of special interest and might be easier to teach due to a very simple general setup. In this case, an oxidation reaction and a reduction reaction occur at the two ends of a single conductive object exposed to an electric field in solution. Such an object is therefore called a bipolar electrode. The nature of the electrochemical reactions and their amplitude can be tuned by playing with the electric field. The fundamental concepts of bipolar electrochemistry are introduced here with a series of basic experiments designed to be carried out in a standard teaching laboratory. These simple and affordable experiments illustrate the key-parameters driving electrochemical reactions at a bipolar electrode. Their influence can be readily visualized using a cheap, commercially available light emitting diode (LED) acting as the bipolar electrode, which illuminates when the current generated by the electrochemical reactions flows through it. The concept of bipolar electrochemistry with eye-catching experiments enables a good introduction to general electrochemistry. It points out the importance of fundamental aspects such as the electric field or the necessity of an electrolyte and a counter-reaction.