Roles of Ruthenium–Support Interactions of Size-Controlled Ruthenium Nanoparticles for the Product Distribution of Fischer–Tropsch Synthesis

A simple aqueous-phase route to the synthesis of ruthenium (Ru) nanoparticles with size in the sub-2-nm regime was prepared by reducing RuCl3 with NaBH4 as a reducing agent in the presence of 6-aminohexanoic acid (AHA) as a capping agent. We found that AHA plays a key role in the formation and distribution of ultrasmall Ru nanoparticles on inorganic supports, with its amine and carboxyl groups serving as a surface-capping agent for the Ru nanoparticles and an anchor to inorganic supports, respectively. The catalytic activity of the size-controlled Ru nanoparticles with sub-2-nm size on various supports, such as TiO2, CeO2, and Vulcan carbon, revealed that a strong metal–support interaction of Ru nanoparticles, especially on carbon support, is responsible for a higher CH4 selectivity during Fischer–Tropsch synthesis.