Ordered mesoporous Pt-Ru-Ir nanostructures as superior bifunctional electrocatalyst for oxygen reduction/oxygen evolution reactions

Sabarinathan Ravichandran; Narayanamoorthy Bhuvanendran; Qian Xu; Thandavarayan Maiyalagan; Lei Xing; Huaneng Su

doi:10.1016/j.jcis.2021.09.171

Ordered mesoporous Pt-Ru-Ir nanostructures as superior bifunctional electrocatalyst for oxygen reduction/oxygen evolution reactions

J Colloid Interface Sci. 2022 Feb 15;608(Pt 1):207-218. doi: 10.1016/j.jcis.2021.09.171. Epub 2021 Sep 29.

Authors

Sabarinathan Ravichandran¹, Narayanamoorthy Bhuvanendran², Qian Xu², Thandavarayan Maiyalagan³, Lei Xing⁴, Huaneng Su⁵

Affiliations

¹ Institute for Energy Research, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China; School of Material Science and Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China.
² Institute for Energy Research, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China.
³ Department of Chemistry, SRM Institute of Science and Technology, Kattankulathur 603203, Tamilnadu, India.
⁴ Department of Engineering Science, University of Oxford, Oxford, OX1 3PJ, United Kingdom.
⁵ Institute for Energy Research, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China. Electronic address: suhuaneng@ujs.edu.cn.

PMID: 34626967
DOI: 10.1016/j.jcis.2021.09.171

Abstract

An efficient oxygen bifunctional catalyst Pt-Ru-Ir with ordered mesoporous nanostructures (OMNs) was successfully synthesized by chemical reduction using KIT-6 mesoporous silica as a template. The crystallographic behavior, electronic effects, and microstructure of the catalysts were investigated by XRD, XPS, SEM, and TEM analysis. The influence of OMNs and the effect of Ir content in Pt-Ru-Ir catalyst on both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) were investigated. The synergistic and electronic effects play an important role in electrocatalytic performance through the electronic coupling between Pt, Ru and Ir followed by the alloy formation with different lattice strain percentages. Amongst, the OMNs Pt₇₀Ru₂₅Ir₅ catalyst exhibits the highest mass activity of 0.21 mA µg^-1 and specific activity of 0.33 mA cm^-2 for ORR, which are nearly 5-fold greater than those for benchmark Pt/C catalyst. Furthermore, the Pt₇₀Ru₂₅Ir₅ demonstrated enhanced OER activity with an overpotential of 470 mV at 10 mA cm^-2, an onset potential of 1.70 V, and a Tafel slope of 118 mV dec^-1, outperforming commercial IrO_2. In addition, the durability of the Pt₇₀Ru₂₅Ir₅ catalyst for ORR and OER are found to be extended in comparison with that of other catalysts reported in this work after 6000 cycles. These results demonstrate that the ordered OMNs Pt-Ru-Ir with low Ir content (∼5 wt%) could be a promising oxygen bifunctional catalyst for electrochemical energy conversion and storage applications.

Keywords: Ordered mesoporous metals; Oxygen evolution reaction; Oxygen reduction reaction; Pt-Ru-Ir; Unitized regenerative fuel cell.