Paired Electrochemical Processes: Overview, Systematization, Selection Criteria, Design Strategies, and Projection

In most commercial electrochemical processes, only one of the two sides of the cell produces a desirable reaction, whereas the complementary reaction at the other side simply avoids interference with the target process and/or offers fast kinetics as not to limit it. An overview of several possible paired reaction schemes and their advantages is given, accompanied with specific thermodynamic and kinetic selection criteria, cell and reaction design strategies, and examples from the organic, inorganic, and environmental areas. The unnecessary nomenclature dispersion in this field (e.g., combined, concurrent, conjugate, convergent, coupled, divergent, dual, duet, linear, paired, parallel, simultaneous and synchronous electrochemical processes) is revised and a simple, consistent classification, as well as a homogeneous schematization system, is proposed.