Comparison of Direct Ink Writing and Binder Jetting for additive manufacturing of Pt/Al₂O₃ catalysts for the dehydrogenation of perhydro-dibenzyltoluene

Two additive manufacturing (AM) techniques, namely extrusion-based Direct Ink Writing (DIW) and powder-based Binder Jetting (BJ), were thoroughly compared to assess their respective advantages and drawbacks for catalyst shaping. The 3D printed monolithic Al₂O₃ supports were wet impregnated with H₃Pt(SO₃)₂(OH) and tested for the dehydrogenation of perhydro-dibenzyltoluene (18H-DBT), a liquid organic hydrogen carrier (LOHC). The supports were analyzed regarding their specific surface area, compression strength, shrinkage behavior and pore size distribution with calcination temperatures ranging from 600 - 1200 °C as well as 3D print specific characteristics. Benefiting the liquid phase reaction, pore diameters below 26 nm were diminished above T_calc = 1050 °C, revealing a BET surface area of 26 m²/g for BJ and 11 m²/g for DIW printed supports. Furthermore, increasing the impregnation duration from 0.5 h to 12 h showed increased Pt loading, larger metal particles, and a deeper penetration into the support. Most notably, for BJ the Pt loading is generally higher due to higher meso- and macroporosity of the support. Catalytic 18H-DBT dehydrogenation with powder and monolithic catalysts showed equal dehydrogenation rates with both 3D printing methods, respectively. The achieved Pt productivity was about 4.3g_H2g_Pt⁻¹min⁻¹ for powder tests and 2.7g_H2g_Pt⁻¹min⁻¹ for monolithic pellets.