Columnar support structures for oxygen reduction electrocatalysts prepared by glancing angle deposition

Columnar titanium structures were fabricated on smooth glassy carbon (GC) disks using the glancing angle deposition (GLAD) physical vapour deposition technique. This catalyst support consists of 500 nm long posts with a nominal cross-sectional diameter of 100 nm. They have a number density of about 10 billion per cm2 which increases the effective surface area of the GC disks by a factor of 13. Platinum films ranging from 10 to 90 nm in thickness (planar equivalent) were deposited onto these posts by magnetron sputtering. The oxygen reduction activity and H2O2 release of these electrocatalysts were measured by the rotating ring-disk electrode method in O2-saturated 0.1 M HClO4 at room temperature. The electrochemical surface area of the catalysts, obtained from Hupd cyclic voltammograms, is about 10–15 times higher than smooth Pt films. The supports can be fabricated from most vacuum-compatible materials and should be stable over a wide range of processing, annealing, and operating conditions.

Columnar titanium structures were fabricated on smooth glassy carbon (GC) disks using the glancing angle deposition (GLAD) physical vapour deposition technique. This catalyst support consists of 500 nm long posts with a nominal cross-sectional diameter of 100 nm. They have a number density of about 10 billion per cm2 which increases the effective surface area of the GC disks by a factor of 13. Platinum films ranging from 10 to 90 nm in thickness (planar equivalent) were deposited onto these posts by magnetron sputtering. The oxygen reduction activity and H2O2 release of these electrocatalysts were measured by the rotating ring-disk electrode method in O2-saturated 0.1 M HClO4 at room temperature. The electrochemical surface area of the catalysts, obtained from Hupd cyclic voltammograms, is about 10–15 times higher than smooth Pt films. (a) Oxygen reduction curves. Anodic sweep rates are shown for 400, 900, and 2500 rpm (grey). A full cycle is shown for 1600 rpm (black). (b) Oxygen reduction curves from the four different Pt loadings at 900 rpm. (c) % H2O2 released in the electrolyte for the four different Pt loadings.Figure optionsDownload as PowerPoint slide