Synergistic MgO Promotion and Binder Effects on the Stable Hydrotreating of Renewable Oils over PtSn/ZSM-5 Catalysts

Sustainable aviation fuel (SAF) production via the hydrotreatment of lipid feedstocks is constrained by excessive cracking, rapid catalyst deactivation, and high hydrogen demand under industrially relevant conditions. Coconut oil was employed as a model renewable lipid feedstock due to its high medium-chain fatty acid content, enabling sensitive probing of cracking severity and coke evolution. Herein, we elucidated how coordinated MgO promotion and alumina binder engineering regulated acidity, metal–support interactions, and coke evolution in PtSn/Z catalysts, resulting in stable conversion and high carbon retention to jet-range liquid hydrocarbons. Physicochemical characterization revealed that MgO progressively neutralized strong acid sites and modified Pt–Sn electronic interactions, while alumina binder incorporation generated hierarchical porosity and stabilized PtSn ensembles through enhanced metal–acid intimacy. Catalytic evaluation during continuous hydrotreating of crude coconut oil demonstrated that moderate MgO loading (1 wt %) effectively suppressed excessive cracking and olefinic coke formation while preserving hydrodeoxygenation and isomerization functions. The optimized PtSn/MgO(1)/Z-Al catalyst achieved sustained jet-fuel-range hydrocarbon selectivity of 57–66% over 100 h time-on-stream under single-step operation at 375 °C and 3 MPa. Deactivation analysis revealed that binder-induced pore architecture redirected coke formation from condensed, micropore-blocking hard coke toward oxygen-rich, labile soft coke, while MgO further suppressed aromatic condensation pathways. As a result, the catalyst design enhanced carbon retention, reduced cracking-induced carbon loss, and enabled hydrogen-rich off-gas recyclability. These results established a scalable catalyst engineering strategy that coupled acidity moderation with catalyst shaping to improve stability, carbon efficiency, and process robustness in renewable oil hydrotreating.