CO hydrogenation on Co/γ-Al2O3 and CoRe/γ-Al2O3 studied by SSITKA

Abstract

catalysts have been studied by the steady-state isotopic transient kinetic analysis (SSITKA) technique. It was found that neither the CO partial pressure, the temperature nor the space velocity influences the in situ CO adsorption. The space velocity, H 2 /CO ratio and temperature was found to affect the intrinsic activity ( s CH 4 ð Þ ) slightly, while the total pressure and syngas partial pressure had only a negligible effect. The surface concentrations and coverages were, however, unaffected by the space velocity, temperature, total pressure, syngas partial pressure and H 2 /CO ratio. All changes, however, affected the methane selectivity, indicating that the methane selectivity was not a function of the surface inventory of methane precursors.

Direct synthesis of methane from CO2/H2O in an oxygen-ion conducting solid oxide electrolyser

“…It is also demonstrated that the heterogeneous catalysis is the rate controlling step in the whole process as the conversion of CO to hydrocarbon (1.8%) in this work is much lower than reported values in Fischer-Tropsch Synthesis from CO/H 2 , which might be attributed to the high temperature and low pressure for the hydrocarbon synthesis process. 33,34 Higher hydrocarbon yield could be obtained by further improving Fischer-Tropsch Synthesis conditions, such as performing coelectrolysis and catalysis in a pressurized system at lower temperatures. For comparison, no methane output was confirmed without the assistance of iron catalyst under the same conditions.…”

Recent Progresses in Understanding of Co-Based Fischer–Tropsch Catalysis by Means of Transient Kinetic Studies and Theoretical Analysis

“…For FTS, the use of SSITKA has resulted in an improved understanding on the effect of catalyst properties (promoters [72][73][74][75][76][77][78][79][80][81][82][83], support [84][85][86][87][88][89][90], particle size etc. [91][92][93][94]) and the reaction conditions [95][96][97][98][99][100][101] on the performance. Concerning the mechanism, SSITKA gives the coverage of CO and surface carbon intermediates and the site coverage of H can be estimated.…”

Dry Reforming of Methane on Rh-Doped Pyrochlore Catalysts: A Steady-State Isotopic Transient Kinetic Study

“…They identified the rate-limiting reaction as the irreversible transformation of CH 4 on metal sites and concluded that CO 2 transformation occurs much faster and is reversible under steadystate conditions. They also observed that the surface concentration of C-containing intermediates was negligible and that the 13 C atom from 13 CH 4 in the feed migrated to form 13 CO 2 , under conditions under which unlabeled CO 2 was fed to the reactor.…”

“…SSITKA is a kinetic analysis technique that provides resolution for the study of active site reaction kinetics that are otherwise inaccessible under solely steady-state conditions. SSITKA has been used extensively in carbon monoxide hydrogenation studies for both supported metal and promoted metal oxide catalysts, − but very few of these studies have examined other C 1 reactions, such as reverse water gas shift (RWGS) or the dry reforming of methane. In addition to revealing information about surface species, SSITKA has also been used to show that oxygen atoms from the lattice of the catalyst material can participate in the reaction pathway. , …”