Preparation of aluminum borate whiskers/CoxCr3-xO4 catalysts on channel surface of cordierite honeycomb ceramic for soot catalytic combustion

Abstract

The monolith catalysts with the hierarchical microstructure prepared from cordierite honeycomb ceramics by the molten salt reaction and the sol–gel impregnation technology. Aluminum borate whiskers (Al₁₈B₄O₃₃) with the lengths of 10–70 µm and the diameters of 0.1–1.4 µm were grown on the channel surface of cordierite honeycomb ceramics, and cilia-like microstructure improve the capture ability of soot in exhaust. A series of spinel-type catalysts Co_xCr_3-xO₄ have loaded on aluminum borate whiskers using the sol–gel impregnation process, and sample Z/C₁C₂-0.25 possess the optimal soot catalytic oxidation activity. The study employed various techniques to characterize morphology and phase composition, including scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Brumauer–Emmett–Teller (BET), Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and thermogravimetric and differential thermal analysis (TG-DTA). The cyclic stability experiments demonstrate that spinel-type catalysts Z/C₁C₂-0.25 exhibits excellent structural stability and consistent catalytic performance. This unique microstructure has great potential applications in the field of DPF.