Stable High-Index Faceted Pt Skin on Zigzag-Like PtFe Nanowires Enhances Oxygen Reduction Catalysis

Mingchuan Luo; Yingjun Sun; Xu Zhang; Yingnan Qin; Mingqiang Li; Yingjie Li; Chunji Li; Yong Yang; Lei Wang; Peng Gao; Gang Lu; Shaojun Guo

doi:10.1002/adma.201705515

Stable High-Index Faceted Pt Skin on Zigzag-Like PtFe Nanowires Enhances Oxygen Reduction Catalysis

Adv Mater. 2018 Mar;30(10). doi: 10.1002/adma.201705515. Epub 2018 Jan 15.

Authors

Mingchuan Luo¹, Yingjun Sun^{1

2}, Xu Zhang³, Yingnan Qin^{1

2}, Mingqiang Li^{4

5}, Yingjie Li¹, Chunji Li¹, Yong Yang¹, Lei Wang², Peng Gao^{4

6}, Gang Lu³, Shaojun Guo^{1

7

8

9}

Affiliations

¹ Department of Materials Science & Engineering, College of Engineering, Peking University, Beijing, 100871, China.
² College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, 266042, China.
³ Department of Physics and Astronomy, California State University, Northridge, CA, 91330, USA.
⁴ Electron Microscopy Laboratory and International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, China.
⁵ Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China.
⁶ Collaborative Innovation Centre of Quantum Matter, Beijing, 100871, China.
⁷ BIC-ESAT, College of Engineering, Peking University, Beijing, 100871, China.
⁸ Department of Energy and Resources Engineering, College of Engineering, Peking University, Beijing, 100871, China.
⁹ Beijing Key Laboratory for Magnetoeletric Materials and Devices (BKL-MEMD), Peking University, Beijing, 100871, China.

PMID: 29333666
DOI: 10.1002/adma.201705515

Abstract

Selectively exposing active surfaces and judiciously tuning the near-surface composition of electrode materials represent two prominent means of promoting electrocatalytic performance. Here, a new class of Pt₃ Fe zigzag-like nanowires (Pt-skin Pt₃ Fe z-NWs) with stable high-index facets (HIFs) and nanosegregated Pt-skin structure is reported, which are capable of substantially boosting electrocatalysis in fuel cells. These unique structural features endow the Pt-skin Pt₃ Fe z-NWs with a mass activity of 2.11 A mg^-1 and a specifc activity of 4.34 mA cm^-2 for the oxygen reduction reaction (ORR) at 0.9 V versus reversible hydrogen electrode, which are the highest in all reported PtFe-based ORR catalysts. Density function theory calculations reveal a combination of exposed HIFs and formation of Pt-skin structure, leading to an optimal oxygen adsorption energy due to the ligand and strain effects, which is responsible for the much enhanced ORR activities. In contrast to previously reported HIFs-based catalysts, the Pt-skin Pt₃ Fe z-NWs maintain ultrahigh durability with little activity decay and negligible structure transformation after 50 000 potential cycles. Overcoming a key technical barrier in electrocatalysis, this work successfully extends the nanosegregated Pt-skin structure to nanocatalysts with HIFs, heralding the exciting prospects of high-effcient Pt-based catalysts in fuel cells.

Keywords: Pt-skin; fuel cells; high-index facet; nanowires; oxygen reduction reaction.