Coupled s-p-d Exchange in Facet-Controlled Pd3Pb Tripods Enhances Oxygen Reduction Catalysis

Lingzheng Bu, Qi Shao, Yecan Pi, Jianlin Yao, Mingchuan Luo, Jianping Lang, Sooyeon Hwang, Huolin Xin, Bolong Huang, Jun Guo, Dong Su, Shaojun Guo, Xiaoqing Huang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

49 Citations (Scopus)

Abstract

Efficient oxygen reduction reaction (ORR) catalysts are key for the development of high-performance fuel cells. Palladium (Pd) is a promising catalyst system for ORR given its potential to replace platinum (Pt); however, it usually exhibits lower activity than Pt. Here, we report a class of ordered Pd3Pb tripods (TPs) with predominantly {110} facets and show that they achieve extremely high ORR performance in alkaline medium. In contrast to the knowledge that the excellent ORR activity of Pt catalyst is caused by its partially filled d orbital, our first-principle calculations suggest that the strong charge exchange between Pd-4d and Pb-(sp) orbitals on the Pd3Pb TPs {110} facet results in a Pd-Pb local bonding unit with an orbital configuration similar to that of Pt. Consequently, Pd3Pb TPs exhibit much higher ORR activities than commercial Pt/C and commercial Pd/C. Pd3Pb TPs are endurable and sustain over 20,000 potential cycles with negligible structural and compositional changes. Efficient catalysts for oxygen reduction reactions (ORRs) are the most decisive factor in high-performance fuel cells to meet energy supplies and industrial needs. Palladium (Pd) has been proposed to catalyze ORR well in alkaline media, but it usually exhibits much lower activity than platinum (Pt). Most reported Pd-based catalysts are limited to zero-dimensional (0D) nanocrystals (NCs), which are not beneficial for improving ORR stability. Moreover, ordered intermetallic NCs are attracting more attention because of their outstanding catalytic properties and high chemical and structural stabilities. Here, we report a class of ordered Pd3Pb tripods (TPs) with predominantly {110} facets. The strong coupled s-p-d exchange effect on {110} faceted Pd3Pb TPs plays a decisive role in boosting ORR, resulting in their greatly enhanced ORR performance over that of Pt/C. This study opens a new route in the rational design of high-efficiency Pd-based catalysts with proper facet and ordering control to enhance ORR catalysis. Guo and colleagues have successfully created a class of ordered Pd3Pb tripods (TPs) with predominantly {110} facets and show that they can achieve an unprecedented ORR activity in alkaline solution. First-principal calculations indicated that the enhanced ORR activity in Pd3Pb TPs can be attributed to a strong coupled s-p-d exchange effect on the {110} facets, which makes Pd3Pb TPs exhibit much higher ORR activities than commercial Pt/C and commercial Pd/C.
Original languageEnglish
Pages (from-to)359-371
Number of pages13
JournalChem
Volume4
Issue number2
DOIs
Publication statusPublished - 8 Feb 2018

Keywords

  • facet control
  • lead
  • oxygen reduction reaction
  • palladium
  • s-p-d exchange
  • tripod

ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry
  • Environmental Chemistry
  • Chemical Engineering(all)
  • Biochemistry, medical
  • Materials Chemistry

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