Figure 1.

Overview of experiments performed. a) In situ 2D X‐ray ptychography of the dried gel Ni/Al₂O₃‐dr sample during calcination, activation, and reaction conditions in a nanoreactor setup. b) Illustration of the sample particles, which are placed on Cu‐pins for ex situ 3D ptychographic tomography experiments. Tomography data was acquired first on the dried gels (Ni/Al₂O₃‐dr and Al₂O₃‐dr), and again on the identical samples following calcination in a muffle furnace (Ni/Al₂O₃‐calc and Al₂O₃‐calc).