Effect of melamine on the oxygen reduction reaction in the n(111)-(111) series of Pt3Co

Abstract

Enhancement of the oxygen reduction reaction (ORR) activity is an important subject for the development of fuel cells. In this study, we prepared the n(111)-(111) series of Pt₃Co single crystal electrodes using an induction heating furnace and investigated the ORR in 0.1 M HClO₄ using the rotation disk electrode (RDE). The specific activity of the ORR (j_k) increased monotonously with increasing terrace width n on the n(111)-(111) series of Pt₃Co, showing the highest activity on Pt₃Co(111). The value of j_k of Pt₃Co(111) was 59-fold higher than that of Pt(111) at 0.95 V(RHE). This trend was different from those of the same series of Pt, Pt₃Co, and Pt₃Ni reported previously. Furthermore, the ORR activity was improved on all electrodes by adding melamine to the electrolytic solution. Melamine was preferentially adsorbed at the terrace edge. Pt₃Co(553) n = 5 showed the highest activity. The values of j_k at 0.95 V(RHE) were 23- and 3.3-fold higher than those of Pt(553) n = 5 and Pt₃Co(553) n = 5 without melamine modification, respectively. The durability of Pt₃Co(553) n = 5 with melamine was improved 8.0-fold.