Fig. 1: SEM survey of the surface morphology of a technical multi-promoted ammonia synthesis catalyst.
From: Decoding technical multi-promoted ammonia synthesis catalysts
a The overview image of the surface structure of the initial catalyst shows a brick wall architecture with iron-rich granules held together by a continuum of promoter material prior to catalytic reaction. b SEM image of the region of interest highlighted in (a) displaying the complex structure in a confluence point of several iron-rich granules. c The close-up look on an iron-rich granule from the region of interest highlighted in (b) denotes the surface morphology covered by a heterogeneously distributed material and a maze-like porous structure of the substrate. d SEM image of the surface of the spent catalyst after 96 h of ammonia synthesis at 90 bar showing platelet, needle-like, and crust-like materials. Conditions of acquisition of (a–c): 22 Pa, H2:N2:Ar = 3:1:0.1.
