Effect of confinement of TiO2 nanotubes over the Ru nanoparticles on Fischer-Tropsch synthesis

Ru nanoparticles (NPs) have been successfully deposited in the inner pores of TiO2 nanotubes (TNTs), denoted as Ru-in/TNT, by vacuum assisted impregnation method for Fischer-Tropsch synthesis (FTS). The composition, morphology and electronic properties have been characterized by the XRD, TEM, N-2-sorption, H-2-TPR/TPD and XPS, investigating the confinement effect of TNT on the entrapped Ru NPs' FTS performance. The Ru-in/TNT exhibits high CO conversion activity and superior deactivation-resist ability over the Ru-out/TNT (with most of Ru NPs deposited on the outer surface of TNT) and Ru/P25 (using commercial P25 powder as support) catalysts. Besides above superiority, the Ru-in/TNT facilitates the formation of long chain (C19+) products as well. The enhanced activity and selectivity can be ascribed to the confinement effect of TNT: (i) strengthen charge transfer and modulate the electronic properties of Ru species resulting in more active center site; (ii) constrain the metal sintering and metal leaching to resist deactivation during FTS; (iii) facilitate the re-adsorption of ce-olefin leading to long-chain product. (C) 2016 Elsevier B.V. All rights reserved