N8 stabilized single-atom Pd for highly selective hydrogenation of acetylene

Maocong Hu, Zhiyi Wu, Zhenhua Yao, Joshua Young, Langli Luo, Yingge Du, Chongmin Wang, Zafar Iqbal, Xianqin Wang

Research output: Contribution to journalArticlepeer-review

Abstract

Single-atom catalysts show a promising future in many reactions even though great challenges still remain such as facile synthesis and long stability. In this work, a single-atom Pd catalyst attached to a designed N8 Lewis base species (Pd1-N8/CNT) is synthesized with cyclic voltammetry (CV) method. The catalyst demonstrates long stability and enhanced C2H4 selectivity in selective hydrogenation of acetylene at 40 °C. CV is carried out in a three-electrode setup with PdO/CNT as the working electrode in NaN3 solution. HAADF-STEM confirms single-atom Pd sites are successfully isolated. XPS measurements and Bader charge calculations indicate N8 is effectively synthesized on CNT substrate after CV treatment while single-atom Pd is stabilized by attaching to the end N of N8. Acetylene-temperature programed desorption (C2H2-TPD) and density functional theory (DFT) calculations suggest C2H2 favors the π bonding on single Pd atom, while H2 dissociates on the N atom (next to Pd) instead of conventionally on Pd. The synergistic effect favors C2H4 formation but prevents full hydrogenation of acetylene to C2H6. This work opens up a new perspective to design and synthesize more selective catalysts with isolated single-atom sites.

Original languageEnglish (US)
Pages (from-to)46-53
Number of pages8
JournalJournal of Catalysis
Volume395
DOIs
StatePublished - Mar 2021
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Physical and Theoretical Chemistry

Keywords

  • Cyclic voltammetry
  • Density functional theory
  • Polynitrogen
  • Selective hydrogenation of acetylene
  • Single-atom catalyst

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