3D Printing Technique Fortifies the Ultradeep Hydrodesulfurization Process of Diesel: A Journey of NiMo/Al₂O₃‑MMT

In this contribution, we rationally designed and controllably fabricated a NiMo/Al₂O₃-montmorillonite (3D-NiMo/Al₂O₃-MMT) monolithic catalyst via a 3D printing strategy with economical montmorillonite (MMT) as a binder. The catalytic performance of the resulting NiMo/Al₂O₃-MMT for 4,6-dimethyldibenzothiophene (4,6-DMDBT) hydrodesulfurization (HDS) was evaluated. The experimental results unveil that the 3D-NiMo/Al₂O₃-MMT monolithic catalyst exhibits robust stability and exceptional HDS activity with 99.2% 4,6-DMDBT conversion (residual 4 ppm of S), which is remarkably superior to that of conventional NiMo/Al₂O₃ (61.5%), NiMo/MMT (63.2%), and even NiMo/Al₂O₃-MMT (76.5%) prepared by the mechanical-mixing method. This should be ascribed to the synthetic effect between the MMT binder and the Al₂O₃ substrate, which effectively weakens the interaction between the Mo species and the Lewis acids on the original Al₂O₃ surface, thereby significantly increasing the content of reducible Mo species and considerably facilitating the formation of more highly active NiMoS phase (Type II) with optimal average stacking layers and thereafter remarkably enhancing the ultradeep HDS activity of the 3D-NiMo/Al₂O₃-MMT monolithic catalyst.