Effective NbOx-Modified Ir/SiO2 Catalyst for Selective Gas-Phase Hydrogenation of Crotonaldehyde to Crotyl Alcohol

Masazumi Tamura, Kensuke Tokonami, Yoshinao Nakagawa, Keiichi Tomishige

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41 Citations (Scopus)


NbOx-modified Ir/SiO2 catalyst (Ir-NbOx/SiO2) showed high activity and selectivity for gas-phase hydrogenation of crotonaldehyde, and Ir-NbOx/SiO2 with Nb/Ir molar ratio of 0.5 (Ir-NbOx/SiO2 (Nb/Ir = 0.5)) provided high crotyl alcohol yield of 87%. This is the highest crotyl alcohol yield among those in gas-phase over reported heterogeneous catalysts. The activities (TOF per surface Ir atom) at low conversion level (40%, W/F = 0.37 gcat·h·mol-1) and high conversion level (97%, W/F = 2.2 gcat·h·mol-1) were calculated to be 0.21 and 0.08 s-1, which are more than 3 times higher than those over reported heterogeneous catalysts. High activity and high yield are derived from the combination of Ir metal with NbOx species. Based on the spectroscopic and kinetic studies, the high activity and high selectivity are attributed to strong adsorption of crotonaldehyde on NbOx species by the high Lewis acidity, and suppression of over-hydrogenation of the produced crotyl alcohol at high conversion level. It is suggested that the formation of hydride species at the interface between Ir metal and NbOx species can promote the selective hydrogenation considering the reaction order with respect to hydrogen pressure. High yield and high activity of Ir-NbOx/SiO2 can contribute to energy saving, cost reduction, and waste reduction, which are directly connected to realization of sustainability.

Original languageEnglish
Pages (from-to)3685-3697
Number of pages13
JournalACS Sustainable Chemistry and Engineering
Issue number5
Publication statusPublished - 2017 May 1


  • Iridium
  • Niobium oxide
  • Selective hydrogenation
  • Unsaturated alcohol

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry
  • Chemical Engineering(all)
  • Renewable Energy, Sustainability and the Environment


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