Improving Oxygen Reduction Performance of Surface-Layer-Controlled Pt-Ni Nano-Octahedra via Gaseous Etching

Can Li; Soonho Kwon; Xiaobo Chen; Lihua Zhang; Anju Sharma; Shaojie Jiang; Hanlei Zhang; Ming Zhou; Jinfong Pan; Guangwen Zhou; William A Goddard 3rd; Jiye Fang

doi:10.1021/acs.nanolett.3c00567

Improving Oxygen Reduction Performance of Surface-Layer-Controlled Pt-Ni Nano-Octahedra via Gaseous Etching

Nano Lett. 2023 Apr 26;23(8):3476-3483. doi: 10.1021/acs.nanolett.3c00567. Epub 2023 Apr 11.

Authors

Affiliations

¹ Department of Chemistry, State University of New York at Binghamton, Binghamton, New York 13902, United States.
² Materials and Process Simulation Center, California Institute of Technology, Pasadena, California 91125, United States.
³ Materials Science and Engineering Program, Department of Mechanical Engineering, State University of New York at Binghamton, Binghamton, New York 13902, United States.
⁴ Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States.
⁵ Analytical and Diagnostics Lab, State University of New York at Binghamton, Binghamton, New York 13902, United States.
⁶ Advanced Materials Characterization Laboratory, Materials Research Center, Missouri University of Science and Technology, Rolla, Missouri 65409, United States.

PMID: 37040582
DOI: 10.1021/acs.nanolett.3c00567

Abstract

This study demonstrates an atomic composition manipulation on Pt-Ni nano-octahedra to enhance their electrocatalytic performance. By selectively extracting Ni atoms from the {111} facets of the Pt-Ni nano-octahedra using gaseous carbon monoxide at an elevated temperature, a Pt-rich shell is formed, resulting in an ∼2 atomic layer Pt-skin. The surface-engineered octahedral nanocatalyst exhibits a significant enhancement in both mass activity (∼1.8-fold) and specific activity (∼2.2-fold) toward the oxygen reduction reaction compared with its unmodified counterpart. After 20,000 potential cycles of durability tests, the surface-etched Pt-Ni nano-octahedral sample shows a mass activity of 1.50 A/mg_Pt, exceeding the initial mass activity of the unetched counterpart (1.40 A/mg_Pt) and outperforming the benchmark Pt/C (0.18 A/mg_Pt) by a factor of 8. DFT calculations predict this improvement with the Pt surface layers and support these experimental observations. This surface-engineering protocol provides a promising strategy for developing novel electrocatalysts with improved catalytic features.

Keywords: Pt-shell {111} facets; deep learning; Pt3Ni nano-octahedron; gaseous etching; oxygen reduction reaction.