Enhanced liquid-solid mass transfer in microchannels by a layer of carbon nanofibers

This paper demonstrates that the observed rate of reaction of the liquid-phase selective hydrogenation of an alkyne is higher for an open and rough carbon nanofiber (CNF) layer positioned on a microchannel wall than for an unsupported flat plate catalyst or dense and smooth CNF layers. This enhancement can be contributed to two phenomena: (1) the kinetic reaction rate increases with a factor of 1.4, due to an increase of the open and freely accessible surface area of the CNF layer available for catalyst deposition; (2) the liquid-solid mass transfer increases with a factor of 2.8, due to an increase in the surface roughness of the CNF layer and the formation of large spherical islands of clustered CNFs. A thin layer of CNFs on a microchannel wall can therefore successfully be used to increase the overall rate of reaction per reactor volume compared to an unsupported flat plate catalyst.