3 years ago

Understanding Composition-Dependent Synergy of PtPd Alloy Nanoparticles in Electrocatalytic Oxygen Reduction Reaction

Understanding Composition-Dependent Synergy of PtPd Alloy Nanoparticles in Electrocatalytic Oxygen Reduction Reaction
Jin Luo, Chuan-Jian Zhong, Valeri Petkov, Haval Kareem, Fangfang Chang, Hannah Cronk, Yinguang Zhao, Shiyao Shan, Jinfang Wu
Gaining an insight into the relationship between the bimetallic composition and catalytic activity is essential for the design of nanoalloy catalysts for oxygen reduction reaction. This report describes findings of a study of the composition–activity relationship for PtPd nanoalloy catalysts in oxygen reduction reaction (ORR). PtnPd100-n nanoalloys with different bimetallic compositions are synthesized by wet chemical method. While the size of the Pt50Pd50 nanoparticles is the largest among the nanoparticles with different compositions, the characterization of the nanoalloys using synchrotron high-energy X-ray diffraction (HE-XRD) coupled to atomic pair distribution function (PDF) analysis reveals that the nanoalloy with an atomic Pt:Pd ratio of 50:50 exhibits an intermediate lattice parameter. Electrochemical characterization of the nanoalloys shows a minimum ORR activity at Pt:Pd ratio close to 50:50, whereas a maximum activity is achieved at Pt:Pd ratio close to 10:90. The composition–activity correlation is assessed by theoretical modeling based on DFT calculation of nanoalloy clusters. In addition to showing an electron transfer from PtPd alloy to oxygen upon its adsorption on the nanoalloy, a relatively large energy difference between HOMO for nanoalloy and LUMO for oxygen is revealed for the nanoalloy with an atomic Pt:Pd ratio of 50:50. By analysis of the adsorption of OH species on PtPd (111) surfaces of different compositions, the strongest adsorption energy is observed for Pt96Pd105 (Pt:Pd ≈ 50:50) cluster, which is believed to be likely responsible for the reduced activity. Interestingly, the adsorption energy on Pt24Pd177 (Pt:Pd ≈ 10:90) cluster falls in between Pt96Pd105 and Pd201 clusters, which is believed to be linked to the observation of the highest catalytic activity for the nanoalloy with an atomic Pt:Pd ratio of 10:90. These findings have implications for the design of composition-tunable nanoalloy catalysts for ORR.

Publisher URL: http://dx.doi.org/10.1021/acs.jpcc.7b03043

DOI: 10.1021/acs.jpcc.7b03043

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.