Oxygen reduction reaction electrocatalytic activity of tilted pt nanorod arrays fabricated by glancing angle deposition

Sputter glancing angle deposition (GLAD) technique was used to fabricate 50 and 200 nm long tilted Pt nanorods on glassy carbon electrodes with weight loadings of 0.042 and 0.117 mg cm −2 , respectively. GLAD-tilted Pt nanorod electrodes were investigated as potential electrocatalysts for proton exchange membrane fuel cells utilizing cyclic voltammetry (CV) and rotating-disk electrode (RDE) techniques in aqueous perchloric acid (HClO 4 ) to determine their oxygen reduction reaction (ORR) activities and stabilities. The CV results demonstrate that the tilted Pt nanorods electrocatalyst exhibits more positive oxide reduction peak potential compared to conventional carbon supported Pt particles (Pt/C), indicating that tilted GLAD Pt nanorods are less oxophilic than Pt/C. In addition, the multiple CV cycles in acidic electrolyte showed that tilted Pt nanorods are significantly more stable than Pt/C. Furthermore, specific ORR activities of tilted Pt nanorods determined by RDE technique were analyzed and compared to literature values of Pt/C and vertically aligned Pt nanorod electrodes. The room temperature RDE results revealed that tilted Pt nanorods demonstrate higher area-specific activity than that of Pt/C catalyst. The enhanced ORR activity of tilted Pt nanorods is due to their large crystallite size and possible dominance of the preferred crystal orientations for ORR. However, the tilted Pt nanorods showed lower mass-specific activity than Pt/C electrocatalyst caused by the large diameters of the tilted Pt nanorods. Overall ORR activity and stability of tilted Pt nanorods were found to be comparable to those of vertical ones.