One-nanometer-thick platinum-based nanowires with controllable surface structures

Pt-based ultrathin nanowires (NWs) are considered as one of the most intriguing catalysts for fuel cells. However, the delicate controllability of surface structure of ultrathin NWs to regulate their catalytic performances is still a challenge. Here, two kinds of one-nanometer-thick Pt-based NWs with smooth surfaces (S-NWs) and rough surfaces (R-NWs) are demonstrated, in which the combined use of hexadecyltrimethylammonium bromide and oleylamine plays an essential role, as they could form soft-templates to direct the growth of NWs. Due to its high-density of low-coordinated sites on the surface, Pt-based R-NWs exhibit higher oxygen reduction reaction (ORR) activities but lower stabilities than corresponding S-NWs. Notably, Pt_0.78Ni_0.22 R-NWs possess the highest mass activity (1.07 Admg_Pt⁻¹) and specific activity (1.02 mAdcm⁻²) among all Pt-based NWs. After 10, 000 sweeping cycles, the mass activity still exhibits 5.7-fold enhancement compared to the corresponding commercial Pt/C. This work presents a new approach to delicately control the surface structure of ultrathin Pt-based NWs as advanced ORR catalysts.