Bipolar Electrochemistry

Bipolar electrochemistry (BPE) is a technique that involves two opposite chemical processes, namely an oxidation and a reduction, occurring simultaneously on the surface of a conducting object, usually without connection to a power supply. The basic phenomenon has already been described and used for many decades but regained a lot of interest in recent years, thanks to several attractive features for developing new applications in various areas ranging from materials science and analytical chemistry to catalysis and even life science. Consequently, BPE has experienced a substantial growth in the number of users and publications. This is mostly due to several advantages over classic electrochemistry, such as the absence of an ohmic contact, the generation of a directional gradient of electroactivity on the object, and the possibility to address simultaneously thousands of objects, which opens the door for high-throughput screening of (electro)chemical properties. Also, some features of this “wireless” electrochemistry allow performing experiments that cannot be achieved with a classic electrochemical setup. Last but not least, only rather low-cost equipment is needed. The objective of the present contribution is to introduce first some fundamental aspects of BPE, and then to illustrate its different developments, highlighting not only the historic landmark achievements, but also the most recent findings, especially in the context of micro- and nanoscience. This article illustrates the singularities and advantages of this straightforward approach and hopefully convinces the reader of the power of this interesting electrochemical concept.