Rational Design of a Perovskite-Type Catalyst for Toluene Oxidation Via Simultaneous Phosphorus Doping and Post-Synthesis Acidic Etching

Perovskite oxides are highly promising catalysts for the combustion removal of volatile organic compounds (VOCs) due to their excellent stability, structural flexibility, and compositional versatility. This study presents a novel perovskite oxide that exhibits enhanced catalytic activity and superior durability for toluene combustion at reduced temperatures. This improvement is achieved by phosphorus doping at the B-site of LaCoO_3-δ (LC) perovskite oxide, followed by post-synthesis acid etching for a proper time. The resulting catalyst demonstrates increased specific surface area, higher total pore volume, and enhanced oxygen vacancy concentration both in the bulk and on the surface. Additionally, the activity of surface lattice oxygen species is significantly improved, leading to enhanced catalytic performance in toluene combustion. Notably, the optimized catalyst shows an exceptionally low activation energy (E_a) of 49.3 kJ mol⁻¹, with a T₉₀ reduction of over 214 ℃ compared to the phosphorus doped LC and 190 ℃ compared to pristine LC. Phosphorus doping plays a main role in significantly improving the long-term durability, particularly in the presence of CO₂ and H₂O, while acid etching boosts the catalytic activity. This work introduces a rational and innovative strategy for optimizing VOC oxidation by improving the structure and surface chemical states of perovskite catalysts.