The hydrogenation of lactic acid to form 1,2-propanediol
has been investigated using Ru nanoparticles supported on carbon as a
catalyst. Two series of catalysts which were prepared by wet impregnation
and sol-immobilization were investigated. Their activity was contrasted
with that of a standard commercial Ru/C catalyst (all catalysts
comprise 5 wt % Ru). The catalyst prepared using sol-immobilization
was found to be more active than the wet impregnation materials. In
addition, the catalyst made by sol-immobilization was initially more
active than the standard commercial catalyst. However, when reacted for
an extended time or with successive reuse cycles, the sol-immobilized
catalyst became less active, whereas the standard commercial catalyst
became steadily more active. Furthermore, both catalysts exhibited an
induction period during the first 1000 s of reaction. Detailed scanning
transmission electron microscopy, X-ray photoelectron spectroscopy and X-ray absorption fine structure analysis data, when
correlated with the catalytic performance results, showed that the high activity can be ascribed to highly dispersed Ru nanoparticles.
Although the sol-immobilization method achieved these optimal discrete Ru nanoparticles immediately, as can be expected from this
preparation methodology, the materials were unstable upon reuse. In addition, surface lactide species were detected on these
particles using X-ray photoelectron spectroscopy, which could contribute to their deactivation. The commercial Ru/C catalysts, on
the other hand, required treatment under reaction conditions to change from raft-like morphologies to the desired small
nanoparticle morphology, during which time the catalytic performance progressively improved
The hydrogenation of lactic acid to form 1,2-propanediolhas been investigated using Ru nanoparticles supported on carbon as acatalyst. Two series of catalysts which were prepared by wet impregnationand sol-immobilization were investigated. Their activity was contrastedwith that of a standard commercial Ru/C catalyst (all catalystscomprise 5 wt % Ru). The catalyst prepared using sol-immobilizationwas found to be more active than the wet impregnation materials. Inaddition, the catalyst made by sol-immobilization was initially moreactive than the standard commercial catalyst. However, when reacted foran extended time or with successive reuse cycles, the sol-immobilizedcatalyst became less active, whereas the standard commercial catalystbecame steadily more active. Furthermore, both catalysts exhibited aninduction period during the first 1000 s of reaction. Detailed scanningtransmission electron microscopy, X-ray photoelectron spectroscopy and X-ray absorption fine structure analysis data, whencorrelated with the catalytic performance results, showed that the high activity can be ascribed to highly dispersed Ru nanoparticles.Although the sol-immobilization method achieved these optimal discrete Ru nanoparticles immediately, as can be expected from thispreparation methodology, the materials were unstable upon reuse. In addition, surface lactide species were detected on theseparticles using X-ray photoelectron spectroscopy, which could contribute to their deactivation. The commercial Ru/C catalysts, onthe other hand, required treatment under reaction conditions to change from raft-like morphologies to the desired smallnanoparticle morphology, during which time the catalytic performance progressively improved
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