Single-Atom La Promoter Breaks the Activity-Stability Trade-Off on Al₂O₃-Supported Pt Catalysts for Propane Dehydrogenation.

Achieving acceptable propane conversion in the endothermic propane dehydrogenation (PDH) reaction demands high temperatures, which exacerbate the activity-stability trade-off through low propylene selectivity and accelerated coking deactivation. Addressing this, we leverage the essence of Le Chatelier's principle-shifting reaction equilibrium through rapid in situ H₂ removal-a strategy conventionally deemed unattainable on Al₂O₃ supports due to hydrogen spillover limitations. The synergistic sites between the La₁₋SnOx promoter and Pt enable the redistribution of surface H species away from the Pt active centers. Consequently, the La₁-Ptn/SnOx/Al₂O₃ catalyst achieves propane conversions approaching the thermodynamic equilibrium conversion over 300-600 °C. Moreover, modulation of hydrogen surface diffusion behavior influences unselective C-C(H) scission of propylene and modifies coke structure and secondary cracking propensity, which is associated with the substantially improved durability observed for La₁-Ptn/SnOx/Al₂O₃ compared to the Ptn/SnOx/Al₂O₃ (commercial mimic) catalyst. This superior performance demonstrates that, the introduction of La₁-SnOx not only overcomes the inert hydrogen-trapping nature of Al₂O₃, but also alleviates the conventional activity-stability trade-off in PDH catalysis, illustrating how atomically dispersed promoters can circumvent intrinsic support limitations and thereby expand the performance boundaries of Al₂O₃-based dehydrogenation catalysts.