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 III, Jiye Fang
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.
Group Members
Li, C., Kwon, S., Chen, X., Zhang, L., Sharma, A., Jiang, S., Zhang, H., Zhou, M., Pan, J., Zhou, G., III, W. A. G., & Fang, J. (2023). Improving Oxygen Reduction Performance of Surface-Layer-Controlled Pt–Ni Nano-Octahedra via Gaseous Etching. *Nano Letters*, *23*(8), 3476-3483. https://doi.org/10.1021/acs.nanolett.3c00567