Eggshell catalysts for Fischer–Tropsch synthesis

A simple preparation method of eggshell Ni/MgO-Al2O3 catalyst for partial oxidation of methane

“…However, some drawbacks exist in the preparation of eggshell catalysts. These include the long preparation period [4], difficulty in control of the eggshell thickness [5] and the content of the active component [6], and the high solvent cost [7]. _________________________ POM to synthesis gas is an attractive and challenging subject for using natural gas [8,9].…”

Synthesis and characterization of Fe–Ni/ɣ-Al2O3 egg-shell catalyst for H2 generation by ammonia decomposition

“…In the case of wet impregnation, the support is wetted before the contact with the active phase solution and the resulting distribution of the precursors is only a consequence of diffusion/adsorption phenomena. However, for dry impregnation, the capillary action, which is responsible for the fast migration of the precursor in the support has to be considered as well [54].…”

“…The higher the viscosity of the solvent, the slower the migration of the front and vice-versa. For instance, Galarraga et al [54], verified that the time it took for an aqueous metal salt solution of Co (0.1 g Co ·ml -1 ) to reach the support core increased from 10 to 60 s as a consequence of adding hydroxyethylcellulose (1 wt.%). The viscosity of the precursor solution at room temperature conditions changed from 2 cP to 40 cP by the addition of a viscosifying agent.…”

“…290 °C), changes of the achieved profile distribution after impregnation were avoided. A fast drying can cause a redistribution of the active phase and even induce a centripetal flow of the solvent that leads to the active phase deposition in the core of the support[38,39,54]. InFigure 2it is evident from the active phase distribution after 2 h that the pores have not been fully filled by the solution.…”

Independence of active substance profiles from the pulse response experimental procedure

“…The reproducibility of catalyst activity has been focused on in many articles and some preparation factors affecting the activity profile have been reported. [3][4][5][6][7] A challenge in this area is to develop a special experimental procedure provide precisely a controlled that can spatial distribution of the catalyst coverage. In our opinion, a strong basis for the development of this procedure is provided by the Temporal Analysis of Products (TAP)-experiment, which is known in heterogeneous catalysis since 1988.…”