Dual-strategy LaMn1-xNixO3-Nano perovskite catalysts via B-site doping and nanocasting for cost-effective mineralization of hazardous hexachlorobutadiene

Hexachlorobutadiene (HCBD), an increasingly threatening persistent organic pollutant, has few mineralization disposal methods due to its high chlorination, thus demanding urgent development of efficient and cost-effective catalytic systems. Herein, LaMn_1-xNi_xO₃-Nano perovskite catalysts were rationally engineered through a dual-strategy combining nanocasting with B-site doping, which exhibited superior oxidation activity toward HCBD. At 250°C and 10 vol% H₂O, the CO₂ yield of LaMn_0.7Ni_0.3O₃-Nano reached 637.89 μg within 90 min, representing a 7.51-fold increase compared to pure LaMnO₃. Notably, this enhancement surpassed the sum of two single-strategy catalysts, including Ni-doped LaMn_0.7Ni_0.3O₃ (1.05-fold increase) and nanocasted LaMnO₃-Nano (4.90-fold increase), demonstrating synergistically enhanced (1 + 1 > 2) HCBD mineralization, along with the best cost-effectiveness (62.43 μg•CO₂/dollar). Comprehensive characterizations revealed that Ni doping induced lattice distortions in MnO₆ octahedra, boosting Mn⁴⁺ /Mn³⁺ active sites to generate reactive oxygen species and increasing acidic sites. Simultaneously, nanocasting significantly enlarged the specific surface area, facilitating catalysts’ adsorption capacity and exposure to active sites. The synergy strengthened redox ability and pollutants dissociation, endowing LaMn_0.7Ni_0.3O₃-Nano with efficient HCBD mineralization and lowest small molecule CVOCs generation. HCBD mineralization mechanism was proposed via qualitative and quantitative analysis of intermediates. Insights from this study provide valuable guidance for recalcitrant pollutants disposal and promising catalyst design.