# Nickel-Based Structured Catalysts for Indirect Internal Reforming of Methane
## Materials and Methods  
Ni-Ce0.85 Sm0.15O2-5 powder (Ni nominal loading 5 wt.%) was synthesized according to the citrate auto-combustion method. Stochiometric amounts of metal nitrates Ni(NO3)2-6H2O, Ce(NO3)3-6H2O, and Sm(NO3)3-6H2O and citric acid monohydrate (CA), with a molar ratio CA/(Ni2+Ce3++Sm3+) = 2, were dissolved in water and well stirred. NH4 OH solution (28 wt.%) was added until pH value 8 was reached. The solvent was evaporated at 100 \({}^{\circ}\)C yielding a gel, then the temperature was increased up to 250 \({}^{\circ}\)C to ignite the auto-combustion. The obtained dark powder was calcined in air at 750 \({}^{\circ}\)C for 5 h with a heating rate of 5 \({}^{\circ}\)C min\({}^{-1}\). After calcination, the powder was milled using a planetary ball mill ([PERSON], Mono Mill Pulverisette 6) at 450 rpm for 3 h. Grinding balls of ZrO2 were used in a 35-mL volume of 2-propanol for a weight of ca. 3 g of powder. The chemical composition was determined by energy dispersive X-ray EDX analysis, as previously reported [29]. The powder was dried at 70 \({}^{\circ}\)C overnight. Hereafter, sample was named Ni-SmDC (samarium doped ceria). Structured catalyst was prepared by wash-coating method, dipping disks (diameter 0.9 mm, thickness 2.5 mm) of NiCrAl foam into a slurry of catalyst powder. The NiCrAl alloy foam (pore size 800 \(\upmu\)m, porosity 90%, geometric surface area 6000 m\({}^{-1}\), density 1250 g\(\cdot\)m\({}^{-3}\)) was supplied by Alantum. Commercial foams were provided with a passivated surface as revealed by a bumpy surface along the struts [19]. A stable slurry of catalyst powder was optimized by choosing solvent, dispersing agent, and organic binder. Specifically, 8 wt.% of triethanolamine, related to catalyst mass, was used as dispersant and 2-propanol was used as solvent. In addition, a low content (2 wt.%) of polyvinyl butyl versin (PVB), named as BUTVAR B-98, was used as organic binder to improve the coating adhesion. The solution was prepared by dissolving triethanolamine and PVB in 2-propanol by ultrasound bath for 30 min at room temperature. Catalyst powder was added to the solution and the slurry was prepared using an ultrasonic processor sonication (Sonics Vibra Cell VCX-600, Newtown, CT, USA), operating for 5 min in pulse mode, to reduce loss of solvent due to heating. Hence, the deposition process was carried out by dipping the foams in the resulting slurry. After dipping, the slurry excess was blown away by an air gun. Multiple coatings cycles were performed to obtain the deposition of a double or a triple layer of catalyst. An intermediate calcination step at 500 \({}^{\circ}\)C for 5 h between two subsequent coating cycles and a final calcination at 750 \({}^{\circ}\)C for 5 h were performed to remove the binder and ensure a good adhesion. The nickel-based catalyst loading was evaluated by the weight difference between the bare and the coated support. Coating adhesion strength was assessed by the weight loss after sonication in 2-propanol (20 min) and drying at 120 \({}^{\circ}\)C for 2 h. The weight loss was 0.4%. The phase composition of powders was investigated by X-ray diffraction (XRD) using a Scintag X1 diffractometer equipped with a Cu K\(\alpha\) (\(\lambda\) = 1.5418 A) source and the Brag-Brentano \(\theta\)-\(\theta\) configuration in the 10-90 2\(\theta\) range, with 0.05\({}^{\circ}\) step size and 3 s acquisition time. The surface area and porosity properties (pore volume and pore size) were measured by N\({}_{2}\) adsorption-desorption isotherms at the temperature of liquid nitrogen (\(-\)196 \({}^{\circ}\)C), using a Micromerities ASAP 2020 instrument. Isotherms were elaborated according to the Brunauer-Emmet-Teller (BET) and Barrett-Joyner-Halenda (BJH) methods in the equilibrium pressure range 0.01 \(<\) P/P\({}^{\circ}\)\(<\) 0.30. The pore size was obtained from the desorption branch of the hysteresis loop using the BJH method.