Hierarchically porous MgAl mixed metal oxide synthesized by sudden decomposition of MgAl layered double hydroxide gel

Abstract

In this study, a hierarchically porous MgAl mixed metal oxide has been synthesized by using MgAl layered double hydroxide gel as a precursor. During the calcination of the precursor, the explosive decomposition of the layered double hydroxide resulted in a number of interconnecting pores. To investigate the formation mechanism, the as-prepared materials were characterized by XRD, SEM, TEM, FT-IR, TG-DSC and nitrogen sorption measurements. Results revealed that the MgAl layered double hydroxide gel was a complicated mixture containing layered double hydroxide, NH₄NO₃, water and organic by-products. At about 188 °C, the formation of a hierarchically porous structure was complete in 3 s because of the instantaneous combustion of organic by-products. The current research provides information for understanding the assembly of the hierarchically porous material under template-free conditions.