3D printed co-precipitated Ni-Al CO₂ methanation catalysts by Binder Jetting: Fabrication, characterization and test in a single pellet string reactor

The Binder Jetting 3D printing technique was used to fabricate spherical Ni-Al CO₂ methanation catalysts from co-precipitated catalyst precursor powder. Catalysts with different nickel loadings were prepared by varying the molar Ni/Al ratio (1/1, 2/1, 3/1, 5/1) during precipitation or the amount of admixed precursor powder (10, 20, 30 wt.%) for printing. XRD and TG analysis revealed phase composition and reducibility characteristics analogous to conventionally prepared Ni-Al catalysts. TEM displayed nickel particle sizes as small as 3.9 nm with a Ni dispersion of up to 13.4 % determined by H₂ chemisorption. Moreover, meso- and macroporous catalyst pellets were generated with a specific surface area of up to 192 m²∕g_cat. The catalysts NiAl11–20, NiAl21–20 and NiAl51–20 were exemplarily tested in a single pellet string reactor where CO₂ conversions of up to 99 % and a high selectivity towards CH₄ was observed at p_tot = 9 bar upon reaching thermodynamic equilibrium.