Chapter 9: Ultrathin Oxide Coatings Synthesized Via Wet Chemical Processes for Electrocatalytic Systems

This chapter describes wet chemical processes for making ultrathin metal oxide coatings and their use in electrocatalytic systems. It is limited to solution-based processes such as the sol–gel deposition (SGD) and the condensed layer deposition (CLD) techniques. Only coatings in the sub-nanometer range (<10 nm), herein referred to as nanocoatings, are discussed. Thicker coatings that are often more easily obtained are not considered. Further, the discussion is centered around coatings made on the commonly used electrode substrate material carbon, in different forms, such as carbon nanotubes and carbon black. Examples are focused on titanium oxide and niobium oxide nanocoatings, which exhibit good stability in acidic electrolytes and possess properties that can be modified by adding dopants. Applications are focused on the use of oxide-encapsulated electrocatalyst supports in acidic electrolytes for electrochemical oxygen reduction.