A novel one-pot method to synthesize hierarchical mesoporous carbon foams with ZnO coating

Abstract

The ever more diverse applications of carbon materials require new fabrication methods to satisfy the demand of functionalization. This work seeks extending functionality of carbon foams known to be determined by their porous properties, which in turn are mainly produced during synthesis. In this work, we report a simple and versatile method to produce hierarchical mesoporous carbon with bottom-up grown crystalline ZnO coating obtained in one pot. The synthesis is based on foaming xylene-epoxy-zinc suspensions, which are further subjected to carbonizing treatments. Two carbon foams carbonized at high (1000 °C) and low (500 °C) temperatures are compared. During carbonization, zinc particles were found to diffuse towards the foam’s surface and evaporate in case of the high temperature process, whereas reaction to form the crystalline ZnO coating was found in the low temperature process. The surface area and pore volume of the carbon foams depend on the carbonizing temperature due to the direct relation with the diffusion rate of particles in the material. This also explains the formation of the oxide layer at the foam external surface observed in the low temperature treatment. This work highlights the possibilities of improving the functionality of porous carbon materials by adding ceramic coatings.