Efficient and Environmentally Friendly Synthesis of AlFe-PILC-Supported MnCe Catalysts for Benzene Combustion

An efficient and environmentally friendly synthesis of AlFe-pillared clay (AlFe-PILC)-supported MnCe catalysts was explored. Mixed AlFe pillaring agents were prepared by a one-step method using Locron L and ferric nitrate solutions at a high temperature and high pressure. Montmorillonite was treated with the AlFe pillaring agents to synthesize AlFe-PILC. MnO and CeO₂ with different Mn/Ce atomic ratios were loaded onto the AlFe-PILC support by an impregnation method. The catalysts were characterized using X-ray diffraction, N₂ adsorption, and high-resolution transmission electron microscopy-energy dispersive spectrometry and were tested for the catalytic combustion of benzene and temperature-programmed surface reaction using a microreactor. Compared to conventional methods, this method is simpler and less costly and results in a larger specific surface area, pore volume, and basal spacing, with the ability to control the structure of the catalytic materials. MnCe(6:1)/AlFe-PILC has the highest catalytic activity and can completely degrade benzene (600 ppm in air) at 250 °C. The activity of the catalyst is stable, and no obvious deactivation is observed at 230 °C after 1000 continuous hours. The catalyst is resistant to water and Cl-poisoning. The amount of CeO₂ added is critical to the dispersion of MnO on the support and the creation of optimum number of oxygen vacancy defect sites for the benzene oxidation reaction. The AlFe-PILC-supported MnCe catalyst is a promising porous material; the support structure, proper dispersion of active species, and addition of Ce are essential for achieving complete degradation of organic toxic chemicals at relatively low temperatures.