Swelling, intercalation, and exfoliation behavior of layered ruthenate derived from layered potassium ruthenate

The intercalation chemistry of a layered protonic ruthenate, H0.2RuO2.1 center dot nH(2)O, derived from a layered potassium ruthenate was studied in detail. Three phases with different hydration states were isolated, H0.2RuO2.1 center dot nH(2)O (n = similar to 0, 0.5, 0.9), and its reactivity with tetrabutylammonium ions (TBA(+)) was considered. The layered protonic ruthenate mono-hydrate readily reacted with TBA(+), affording direct intercalation of bulky tetrabutylammonium ions into the interlayer gallery. Fine-tuning the reaction conditions allowed exfoliation of the layered ruthenate into elementary nanosheets and thereby a simplified one-step exfoliation was achieved. Microscopic observation by atomic force microscopy and transmission electron microscopy clearly showed the formation of unilamellar sheets with very high two-dimensional anisotropy, a thickness of only 1.3 +/- 0.1 nm. The nanosheets were characterized by two-dimensional crystallites with the oblique cell of a = 0.5610(8) nm, b = 0.5121(6) nm and gamma = 109.4(2)degrees on the basis of in-plane diffraction analysis. (C) 2009 Elsevier Inc. All rights reserved.