Nanoscale observations of the effect of cobalt on calcite growth and dissolution

Abstract

In situ atomic force microscopy has been used to study the effect of dissolved cobalt on the growth and dissolution of calcite {10.4} surfaces. Growth experiments conducted in the presence of various cobalt concentrations revealed that the growth of the first layer proceeds with step growth and is faster than the growth in pure solution. The subsequent growth on the newly formed surfaces is much slower, although the solution supersaturation is kept constant. This difference in the step velocity leads to the temporary reproduction of the original surface topography (template effect). This demonstrates the role of the substrate surface structure in the crystal growth. In situ dissolution experiments conducted in the presence of cobalt revealed that cobalt is sorbed at the negative (acute) kinks leading to the formation of monomolecular semi-triangular etch pits.