Exfoliation of a two-dimensional cationic inorganic network as a new paradigm for high-capacity Cr-anion capture.

We have discovered a rare example of a non-LDH cationic inorganic layered material [Cu(OH)][OS(CH)SO]. Its in situ exfoliation achieves record high adsorption capacities for chromate and dichromate. This phenomenon is ascribed to the combination of the strong host-anion electrostatic interactions and the high surface area of our cuprate material, which overcomes the memory effect problem of LDHs. Moreover, our material also selectively captures Cr with a negligible decrease in capacity when non-toxic, monovalent anions are present.