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Experimental and First‐Principles Evidence for Interfacial Activity of Ru/TiO 2 for the Direct Conversion of m ‐Cresol to Toluene
Author(s) -
Omotoso Taiwo O.,
Baek Byeongjin,
Grabow Lars C.,
Crossley Steven P.
Publication year - 2017
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201700157
Subject(s) - toluene , cleavage (geology) , chemistry , metal , catalysis , bond cleavage , chemical engineering , organic chemistry , materials science , fracture (geology) , engineering , composite material
The selective cleavage of C−O bonds in phenolic species is perhaps the most difficult transformation required for converting biomass‐derived monomers to aromatic fuels and chemicals. Metals supported on reducible oxides, such as Ru/TiO 2 , have demonstrated considerable promise for a variety of selective C−O cleavage reactions, but the active site has been subject of a great deal of speculation. This paper employs a combination of theory and experiments to investigate the nature of the active site for the selective transformation of m ‐cresol to toluene. Through variation of metal loading, particle size and support phase, we show that sites responsible for direct C−O cleavage of m ‐cresol lie at the perimeter of the metal particle. The activation barrier for C−O cleavage is reduced from 1.4 eV on the Ru surface to 0.7 eV at an interfacial site. The introduction of water facilitates a further reduction to 0.3 eV via a proton‐assisted C‐O cleavage. These results answer a longstanding question regarding the nature of these important active sites, with broad implications for biomass upgrading.