Enhanced propylene oxide selectivity for gas phase direct propylene epoxidation by lattice expansion of silver atoms on nickel nanoparticles

Bin Yu, Tuğçe Ayvalı, Elizabeth Raine, Tong Li, Molly Meng Jung Li, Jianwei Zheng, Simson Wu, Abdulaziz A. Bagabas, Shik Chi Edman Tsang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

17 Citations (Scopus)


A series of surfactant-free nickel-core and silver-shell (Ni@Ag) nanoparticles encapsulated within the mesopores of SBA-15 were synthesized and tested as catalysts for direct propylene oxidation by molecular oxygen. The influences of temperature, Gas Hour Space Velocity (GHSV) and Ni/Ag ratio on catalytic activity were systematically investigated. Among the prepared samples, Ni1Ag0.4/SBA-15 exhibited the best catalytic performance with selectivity of 70.7% and PO production rate of 4.4 nmol/g/s under 1 bar at 220 °C with GHSV of 192 h−1. High selectivity was attributed to longer Ag-Ag interatomic distance obtained by careful engineering the thickness of Ag shell over preformed Ni nanoparticles. In addition, all prepared new Ni@Ag core-shell catalysts presented excellent stability, which could maintain the conversion and selectivity for at least 10 h. These results suggest that new designs based on Ag surface atoms tailoring might pave the way to highly efficient and robust Ag catalysts for direct propylene oxidation using molecular oxygen as sole oxidant.

Original languageEnglish
Pages (from-to)304-312
Number of pages9
JournalApplied Catalysis B: Environmental
Publication statusPublished - Apr 2019
Externally publishedYes


  • Core-shell nanoparticle
  • Epoxidation
  • Lattice expansion
  • Propylene
  • Silver-nickel

ASJC Scopus subject areas

  • Catalysis
  • Environmental Science(all)
  • Process Chemistry and Technology

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