Front and end zones of Rh/Ce0.75Zr0.25O2−δ-ƞ-Al2O3/FeCrAl wire mesh catalytic module were studied by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) techniques after more than 250 h on stream under hydrocarbon fuels steam (SR) and autothermal reforming (ATR) conditions. Catalyst coking by fibrous carbon growth under diesel ATR conditions was confirmed. This process was mainly located on the surface of the catalytic coating and did not induce exfoliation and damage of coating. Coking was attributed to contamination by iron, which was confirmed by TEM and energy-dispersive X-ray spectroscopy (EDX). Despite catalyst carbonization, the composite catalyst was shown to be stable and regeneratable under hydrocarbon ATR and SR conditions, no morphology and microstructure degradation was identified in both front and end zones of the monolith.