Enhancing Toluene Combustion Activity and Sulfur Resistance of Co-Based Catalysts via La–Mg Synergistic Modification of γ-Al ₂ O ₃

LaMg-modified Co/γ-Al2O3 catalysts underwent controlled quantitative sulfur poisoning through in situ thermal decomposition of ammonium sulfate solution, followed by catalytic combustion of toluene as a probe reaction for performance evaluation. The optimal Co/LaMg(2:1)@γ-Al2O3 catalyst achieved complete toluene conversion at 280 °C, and even after sulfur poisoning its full-conversion temperature increased only to 300 °C, demonstrating excellent activity and sulfur tolerance. The superior performance arises from synergistic structural modifications: the uniformly dispersed MgSO4 with regulated La2(SO4)3 formation mitigates sulfate-induced pore collapse by forming a protective surface layer. Simultaneously, La2O3 anchors the sulfate species and prevents direct contact between MgSO4 and Co3O4 crystallites, thereby preserving the active Co3O4 phase and its lattice oxygen mobility. This dual-functional strategy simultaneously stabilizes active sites and maintains efficient oxygen utilization, thereby achieving exceptional sulfur tolerance and sustained catalytic performance. This combined approach achieves sustainable catalytic performance under sulfur-poisoned conditions through spatial separation of sulfate accumulation and active site preservation.