Dynamic hydrogen bubble templating of Ni (Ni DHBT) electrodes was used to prepare highly porous films with enhanced properties towards the oxygen evolution reaction (OER). Upon varying the electrodeposition conditions, Ni films with a macroporous primary structure and highly porous cauliflower-like secondary structure were formed. These films are able to develop an extended electrochemically active surface area, up to 270-fold increase compared to Ni plate. They exhibit stable overpotential ( 250 = 540 mV) at j = 250 mA cm-2 geometric in 1M KOH electrolyte, which is 300 mV less positive than at Ni plate. Fe incorporation onto these Ni DHBT structures can further lower OER overpotentials to  250 = 310 mV. Ni DHBT films are remarkably stable over prolonged polarization and are characterized by a low Tafel slope (29 mV/ decade) that extends up to j =100 mA cm-2 geometric , attributed to both superaerophobic characteristics with a contact angle of ca 160° between the surface and an air bubble and superhydrophilic characteristics with less than 25° between the surface and a water droplet.

Preferentially (100)-oriented nanostructured platinum films were modified by subsequent surface functionalization with iridium through pulsed electrodeposition. The Ir surface coverage was adjusted by varying the number of applied electrodeposition pulses, and was found to modify the reactivity towards NH 3 oxidation. Deposition of minute amount of Ir atoms ([Ir] = 6 at%) at the surface of preferentially (100)-oriented Pt leads to a decrease in the NH 3 oxidation onset potential (from À430 to À500 mV vs. Hg/HgO), an increase in the current density (at À0.30 V) from 0.55 to 0.67 mA cm À2 , and an increase in the poisoning resistance over polarization at constant potential. This is attributed to the preferential adsorption of Ir atoms at Pt (100) step sites close to the Pt(100) terraces that are known to be the more active for the electro-oxidation of NH 3 .

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