Engineering of Surface Environment of Pd Nanoparticle Catalysts on Carbon Support with Pyrene-Thiol Ligands for Semihydrogenation of Alkynes

Takeharu Yoshii, Daiki Umemoto, Yasutaka Kuwahara, Kohsuke Mori, Hiromi Yamashita

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

A new type of pyrene-thiol derivative-modified Pd nanoparticle (NP) catalyst on a carbon black support for the efficient semihydrogenation of alkynes to alkenes is reported herein. Colloidal Pd NPs surrounded by pyrene-thiol modifiers were prepared using the two-phase Brust method followed by impregnation of carbon black materials. Based on the structural characterization of the prepared catalyst (PyC12S-Pd/VC) by NMR, UV-vis, FT-IR, TEM, HAADF-STEM, Pd K-edge XAFS, XRD, N2 adsorption, and XPS, we show that highly dispersed Pd NPs are immobilized on the catalysts via Ï€-πinteraction between pyrene groups bound to the Pd NPs and carbon black supports. PyC12S-Pd/VC efficiently catalyzes the alkyne semihydrogenation reaction while maintaining high alkene selectivity; an alkene selectivity of 94% is attained at 98% conversion after 5 h of reaction, and the selectivity was retained around 80% in 10 h of reaction. This performance is superior to that of a catalyst without pyrene groups and that of a commercial Lindlar catalyst. The steric hindrance of pyrene groups restricts access of the substrates to Pd NP surfaces, suppressing the unfavorable overhydrogenation of alkenes to alkanes, which is revealed by the solvent and substrate dependency on the catalytic performance and a DFT calculation study. Furthermore, the high selectivity and stability of PyC12S-Pd/VC are caused by the strong interaction between pyrene groups and carbon supports, which prevents the separation of pyrene modifiers and the leaching or sintering of Pd NPs during the catalytic reaction. It is demonstrated that the combination of Pd NPs, pyrene-thiol modifiers, and carbon supports offers high activity, alkene selectivity, and stability in the semihydrogenation reaction.

Original languageEnglish
Pages (from-to)37708-37719
Number of pages12
JournalACS Applied Materials and Interfaces
Volume11
Issue number41
DOIs
Publication statusPublished - 2019 Oct 16
Externally publishedYes

Keywords

  • Pd nanoparticles
  • heterogeneous catalysis
  • pyrene-thiol ligands
  • semihydrogenation
  • surface modification

ASJC Scopus subject areas

  • Materials Science(all)

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