Synthesis, Characterization, Uses and Applications of Porous Clays Heterostructures: A Review.

Porous clay heterostructures (PCH) are obtained by the insertion of an organic bulky cation in the interlayer spacing of a smectite, causing a swelling of the clay mineral. Right after, oxides species, mainly silicon oxide, are incorporated as pillars galleries between adjacent layers to form a porous structure after the removal of the template. The ordering of the clay mineral as well the organic cation incorporated in the synthetic step favors the modulation of the textural properties of the PCH. In addition, the incorporation of heteroatoms in the pillars galleries can also modulate the acidity of the PCH. The modulation of the pore size and the acid properties provides to these materials a wide range of applications in the fields of adsorption and catalysis. This paper carries out a detailed review of the synthesis of PCH, characterization as well as uses and application reported in the literature.