Ethanol-ethylene conversion mechanism on hydrogen boride sheets probed byin situinfrared absorption spectroscopy

Asahi Fujino, Shin Ichi Ito, Taiga Goto, Ryota Ishibiki, Ryota Osuga, Junko N. Kondo, Tadahiro Fujitani, Junji Nakamura, Hideo Hosono, Takahiro Kondo

Research output: Contribution to journalArticlepeer-review

Abstract

Two-dimensional hydrogen boride (HB) sheets were recently demonstrated to act as a solid acid catalyst in their hydrogen-deficient state. However, both the active sites and the mechanism of the catalytic process require further elucidation. In this study, we analyzed the conversion of ethanol adsorbed on HB sheets under vacuum during heating usingin situFourier transform infrared (FT-IR) absorption spectroscopy with isotope labelling. Up to 450 K, the FT-IR peak associated with the OH group of the adsorbed ethanol molecule disappeared from the spectrum, which was attributed to a dehydration reaction with a hydrogen atom from the HB sheet, resulting in the formation of an ethyl species. At temperatures above 440 K, the number of BD bonds markedly increased in CD3CH2OH, compared to CH3CD2OH; the temperature dependence of the formation rate of BD bonds was similar to that of the dehydration reaction rate of ethanol on HB sheets under steady-state conditions. The rate-determining step of the dehydration of ethanol on HB was thus ascribed to the dehydrogenation of the methyl group of the ethyl species on the HB sheets, followed by the immediate desorption of ethylene. These results show that the catalytic ethanol dehydration process on HB involves the hydrogen atoms of the HB sheets. The obtained mechanistic insights are expected to promote the practical application of HB sheets as catalysts.

Original languageEnglish
Pages (from-to)7724-7734
Number of pages11
JournalPhysical Chemistry Chemical Physics
Volume23
Issue number13
DOIs
Publication statusPublished - 2021 Apr 7
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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