Oxygen Reduction Catalysis on Model Pt Electrodes

The use of model electrodes, particularly single crystals, represents a unique opportunity to better understand the performance of real-world (nanostructured) materials: identify active sites, elucidate factors responsible for selectivity and stability of the catalytic centers.

This approach is of growing importance for the electrocatalysis of the oxygen reduction reaction (ORR), which is nowadays one of the key reactions for both fundamental science and various technological applications. The latter include promising automotive applications or larger scale industrial processes, where it is involved in modern schemes of electrolytic production of chlorine (so-called oxygen depolarized cathode technology). From the point of view of fundamental science, the ORR has become an important model process which is critical for better understanding of reactions at electrified solid / liquid interfaces.

The common way of improving the activity of Pt towards ORR and many other reactions is a modification of the electronic properties of the surface through alloying it with other (mostly transition) metals. One can distinguish approaches which are based on “bulk”, “sub-surface” and “surface” alloying. Additionally, introduction of specific (often quasi-periodic) defects can also result in a drastic increase in the ORR activity. In the presentation, examples will be given of how the above-mentioned approaches can be used to design active surfaces; and how the model electrodes can help in better understanding of the performance of electrocatalytic systems.