Heterogeneous Catalysts

Electrochemical route is probably one of the most cost‐effective synthesis methods of functional and nanostructured thin films because it does not require expensive or complicated apparatus. It also offers great versatility in fabricating thin film with various desired properties by simply modulating a few operating parameters. All electrochemical methods discussed in this chapter are based on the same principle of electrochemistry that the deposition is a result of redox reactions and the migration behavior of charged elements given an applied voltage or current (i.e. anodization, cathodic electrodeposition, and electrophoretic deposition). Changing the ways of voltage/current being applied to the system (e.g. through the introduction of pulse) can also have great influence in the quality of the deposition process.

Current status of electrochemical thin film synthesis has seen the domination of catalytic materials with relatively simple composition. In many cases, metal oxides in the form of binary oxides are produced. Modulation of their morphology using electrochemical methods (as described in this chapter) and the subsequent investigation on the impact of such morphological control offer new opportunity in improving the overall reaction kinetics. Recent trend in nanostructuring the catalytic materials in thin film configuration will continue. Electrochemical synthesis of nanostructured catalytic thin film can also offer the opportunities in exploring new catalytic materials beyond the currently dominant simple oxide (or other simple composition). Introduction of secondary component in the making of composite materials and the transformation of simple oxide into ternary/quaternary counterparts may become an apparent alternative in the near future to prepare complex functional catalytic thin films. The matrix of composition afforded by electrochemical synthesis of thin films might also be helpful in discovering new catalytic reactions.

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