In situ impregnated Ni/Al₂O₃ catalysts prepared by binder jet 3D printing using nickel nitrate-containing ink

The binder jetting printing technique enables in situ impregnation of alumina using a Ni(NO₃)₂-containing ink (NI), facilitating omission of impregnation. NI was compared to wet impregnation (WI). Full characterization by quasi-in situ XPS, XAS and TPR revealed the presence of Ni as NiAl₂O₄ spinel. TPR analysis identified surface NiO and NiAl₂O₄ species with facilitated reduction by NI, in addition to the respective species in bulk form. Post-processing affects active site accessibility by coverage. 3D printing limited the Ni loading, but XPS revealed higher metal dispersion by NI. CO₂ hydrogenation confirmed active Ni/Al₂O₃ catalysts with enhanced activity by NI.