Structure-switchable mesoporous carbon hollow sphere framework toward sensitive microwave response

Abstract

Mesoporous carbon hollow sphere (MCHS) is one of the most significant functional materials in various fields. Unfortunately, systematically regulating microstructure of MHCS has been rarely investigated so far. In this work, using one unique simultaneous-hydrolyzation-polymerization process, we are able to precisely control the morphology configurations of MCHS, including its shell thickness and integrate size, hollow void and mesopore in the shell. The shell thickness and integrate size are associated with the synergistic effect of hydrolyzation and polymerization reactions. The hollow void and mesopore are determined by the SiO2 template morphology. Thus, a series of MCHSs with controlled microstructure were achieved through elaborately tuning the precursor. More importantly, different types of MCHSs demonstrate significantly different dielectric and microwave absorbing properties due to the discrepancy of volume ratio between pores and carbon compositions. The typical sample could achieve a broad effective absorption bandwidth of 5.9 GHz and 6.5 GHz with a thickness of 2.35 mm and 2.65 mm, respectively, at a filling ratio of only 20 wt%. These encouraging results significantly promote a deeper understanding of the fundamental chemistry mechanism for constructing MCHS as well as using the material as potential candidate for solving microwave interference issue.