Catalytic effects of ruthenium particle size on the Fischer–Tropsch Synthesis

• Published in: Journal of catalysis 2011-11, Vol.284 (1), p.102-108
• Main Authors: Carballo, Juan María González, Yang, Jia, Holmen, Anders, García-Rodríguez, Sergio, Rojas, Sergio, Ojeda, Manuel, Fierro, José Luis G.
• Format: Article
• Language: English
• Subjects: active sites; adsorption; Carbon monoxide; Catalysis; catalysts; Chemical elements; Chemical synthesis; Chemistry; Exact sciences and technology; Fischer–Tropsch; General and physical chemistry; Hydrocarbons; hydrogen; Kinetics; particle size; ruthenium; SITTKA; Size effects; Surface physical chemistry; temperature; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/j.jcat.2011.09.008

Ru size matters: This work investigates the catalytic consequences of Ru cluster size (4–23 nm) in the Fischer–Tropsch Synthesis. This reaction is structure sensitive when Ru < 10 nm: turnover frequency of CO consumption increases as Ru size increases from 4 to 10 nm, reaching a constant value for larger clusters. [Display omitted] ► The performance of Ru catalysts for the synthesis of hydrocarbons is dominated by Ru particle size. ► Ru particles between 8–10 nm show the maximum rate for hydrocarbon production. ► Fischer–Tropsch Synthesis is a structure-sensitive reaction when Ru particles are smaller than 10 nm. This work investigates the catalytic consequences of Ru cluster size in the Fischer–Tropsch Synthesis (FTS). Ru/Al 2O 3 catalysts with different metal particles size have been obtained by treating the solid in pure H 2 at increasing temperatures and times. Steady-state isotopic transient kinetic analysis (SSITKA) has been carried out at 523 K, 5.5 kPa CO, 55 kPa H 2, and 124.5 kPa inert in order to determine surface residence times and coverage of reversibly bonded CO and CH x intermediates as a function of Ru particle size (4–23 nm). We have found that FTS with Ru-based catalysts is a highly structure-sensitive reaction when Ru < 10 nm. In this range, turnover frequency of CO consumption (TOF CO) increases as the particle size increases, reaching a constant value for Ru particles larger than 10 nm. The lower intrinsic activity shown by Ru clusters