Controllable Assembly of Hierarchical Macroporous–Mesoporous LnFeO3 and Their Catalytic Performance in the CO + NO Reaction

A new synthesis strategy to prepare hierarchical macroporous–mesoporous materials employing poly(ethylene oxide)-poly(phenylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) as a single template and an acid adjusting agent was reported. There is a hierarchical structure including macropores with a size of 50–100 nm and mesopores in the macroporous walls with a size of 3–5 nm. The macroporous walls are composed of rare earth orthoferrite nanoparticles with a size of 5–10 nm. These hierarchically porous materials show high catalytic activities for the CO + NO reaction, and NO can be fully converted to N2 at temperatures as low as 350 °C, indicating their potential in the catalytic conversion of automotive exhaust gas and other catalysis-related fields. This synthesis strategy is a facile method for the preparation of hierarchical porous materials and may give us a guideline for the synthesis of functional materials with further catalytic applications.