Observation of Staging during Intercalation in Layered α-Cobalt Hydroxides: A Synthetic and Kinetic Study

Abstract

The anion-exchange reaction of the layered α-cobalt hydroxides Co(OH)1.75(DDS)0.25·0.6H2O (1) and Co(OH)1.7Cl0.3·0.4H2O (3) with carbonate has been investigated. For 3 the reaction proceeds by complete displacement of the interlayer Cl− anions by CO32− to give Co(OH)1.7(CO3)0.15·0.6H2O (4). Remarkably for 1 we only observe ion-exchange of the DDS− from every other layer to give the second stage intercalate Co(OH)1.75(DDS)0.07(CO3)0.09·0.5H2O (2). The kinetics of these processes have been investigated using time-resolved in situ energy dispersive XRD and small/wide-angle X-ray scattering. In both cases the reaction order (n) was found to be consistent with a two-dimensional diffusion controlled model. Both 3 and 4 are magnetically ordered, and dc and ac magnetic susceptibility measurements have been used to explore their 3D ferrimagnetically ordered ground states