Electrocatalysts are the heart of power devices where electricity is produced via conversion of chemical into electrical energy. - pressive advances in surface science techniques and in first pr- ciples computational design are providing new avenues for signi- cant improvement of the overall efficiencies of such power dev- es, especially because of an increase in the understanding of el- trocatalytic materials and processes. For example, the devel- ment of high resolution instrumentation including various electron and ion-scattering and in-situ synchrotron spectroscopies, elect- chemical...