Ageing Effects on Exhaust Gas Catalysts: Microscopic Changes Captured by X-Ray Tomography

Aging of a Pt/Al2O3 exhaust gas catalyst monitored by quasi in situ X-ray micro computed tomography

“…In a recent study we followed aging effects across several temperature steps 27 and found 950 C to cause the highest impact on the catalyst layer (crack formation, sintering). Consequently, here we conducted isothermal aging at 950 C in a static air furnace for 4, 8, 12, and 24 h to provoke formation of pronounced features on the same sample and observe the effect of aging time.…”

“…Additionally, it is always questionable how representative the sample under investigation is, e.g., if using focused ion beam scanning electron microscopy (FIB-SEM). 1,4 In contrast to these methods, X-ray absorption micro-computed tomography (m-CT) can be used in a nondestructive way 26,27 as was rst demonstrated for sintering of glass powders with 150 mm grains using ex situ treatments. 28 Moreover, X-ray tomography in uorescence and diffraction mode was used to investigate coated foams 29 and combined with multiple electron microscopy tomography techniques to study sample porosity across several length scales.…”

Micro-CT at the imaging beamline P05 at PETRA III

“…The scientific topics covered in user experiments so far include materials science, medicine, biology and geology first published examples are e.g. the investigation of the ageing of an exhaust gas catalyst [3] and the analysis of the head morphology of a silverfish [4]. Due to generous space around the sample extended sample environments can easily be implemented.…”

Modeling reaction–diffusion processes within catalyst washcoats: I. Microscale processes based on three-dimensional reconstructions

“…The pore-size distributions are obtained experimentally using a nitrogen absorption measurements or mercury porosimetry, while SEM and TEM images are used to determine the particle and pore sizes [6,9]. Reconstructed models use recent advances in microscopy, enabling three-dimensional imaging of the porous catalytic materials at high resolution [10][11][12][13][14]. Methods for high-resolution microscopy include X-ray tomography [15][16][17][18][19][20] or FIB-SEM techniques [21][22][23][24][25][26] to reconstruct the microporous structure of the catalysts.…”