Facile synthesis of highly stable and well-dispersed mesoporous ZrO2/carbon composites with high performance in oxidative dehydrogenation of ethylbenzene

Abstract

Highly ordered mesoporous ZrO₂/carbon (FDU-15) composites have been synthesized via a facile evaporation induced triconstituent co-assembly (EISA) approach by using Pluronic F127 as a template and zirconium oxychloride octahydrate and resol as Zr and carbon sources. The synthesized mesoporous composites exhibit a highly ordered two-dimensional (2-D) hexagonal mesostructure with relatively high specific surface areas (up to 947 m² g⁻¹), pore sizes around 3.8 nm and high pore volumes (up to 0.71 cm³ g⁻¹). The results clearly show that the crystalline zirconia nanoparticles (ca. 1.9–3.9 nm) are well-dispersed in amorphous matrices of the ordered mesoporous carbon FDU-15 materials, which construct the nanocomposites. The ordered mesostructures of the obtained ZrO₂/FDU-15 composites can be well-retained even at the high pyrolysis temperature (up to 900 °C), suggesting a high thermal stability. The zirconia content of the ZrO₂/FDU-15 composites can be tunable in a wide range (up to 47%). Moreover, the resultant mesoporous ZrO₂/FDU-15 composites exhibit high catalytic activity in oxidative dehydrogenation (ODH) of ethylbenzene (EB) to styrene (ST), with high ethylbenzene conversion (59.6%) and styrene selectivity (90.4%), which is mainly attributed to the synergistic catalytic effect between the oxygen-containing groups located on the carbon pore walls and weakly basic sites of the nanocrystalline ZrO₂. Furthermore, the high specific surface areas and opening pore channels are also responsible for their high catalytic activity. Therefore, it is a very promising catalyst material in styrene production on an industrial scale.