Nano-size effects of NH4Al(OH)2CO3 on construction CeO2-ZrO2-Al2O3 materials with high performance

Abstract

Nanomaterials have been widely used in environmental catalysis and size dependency of these nanomaterials has always been a focus of intensive studies for technological applications. In this paper, a serials of NH4Al(OH)2CO3 (AACH) with different crystal size (6.3, 7.6, 8.8, 10.0 and 12.7 nm) was achieved through growth control by a facile hydrothermal treatment at different temperatures, after which the CeO2-ZrO2-Al2O3(CZA) materials were prepared through a deposition-precipitation method. Then the size dependencies of textural properties, thermal stability and redox properties in CZA materials were disclosed. The results indicate that the crystal size of AACH not only affected the driving force of sintering, but also played a significant role in coordinating the interaction among the multi-components. Among these materials, the AACH with moderate crystallite size of 8.8 nm facilitates to improve the thermal stability of pore structure, highly disperse CeO2-ZrO2(CZ) nanoparticles, adjust the interaction between Al2O3 and CZ, to form homogeneous CZ solid solution. Consequently, when the grain size of AACH is 8.8 nm, the resulting CZA material exhibits the largest specific surface, the lowest reduction temperature, the most active oxygen species and the best soot oxidation activity even being thermally aged at 1000 °C for 4 h compared with others.