Cyclic Voltammetry Analysis of Electrocatalytic Films

Contemporary energy challenges require the catalytic activation of small molecules such as H₂O, H⁺, O₂, and CO₂ in view of their electrochemical reduction or oxidation. Mesoporous films containing the catalyst, conductive of electron or holes and permeable by the substrate appearance, when coated onto the electrode surface, as a convenient means of carrying out such reactions. Cyclic voltammetry then offers a suitable way of investigating mechanistically the interplay between catalytic reaction, mass, and charge transport, forming the basis of rational strategies for optimization of the film performances and for benchmarking catalysts. Systematic analysis of the cyclic voltammetric responses of catalytic films reflecting the various mechanistic scenarios has been lacking so far. It is provided here, starting with simple reaction schemes, which provides the occasion of introducing the basic concepts and relationships that will serve to the future resolution of more complex cases. Appropriate normalizations and dimensionless formulations allow the definition of actual governing parameters. The use of kinetic zone diagrams provides a precious tool for understanding the functioning of the catalytic film