Nanosheets of layered perovskite-like oxides attract researchers as building blocks for
the creation of a wide range of demanded nanomaterials. However, Ruddlesden–Popper phases
are difficult to separate into nanosheets quantitatively via the conventional liquid-phase exfoliation
procedure in aqueous solutions of bulky organic bases. The present study has considered
systematically a relatively novel and efficient approach to a high-yield preparation of concentrated
suspensions of perovskite nanosheets. For this, the Ruddlesden–Popper titanates HLnTiO4 and
H2Ln2Ti3O10 (Ln = La, Nd) have been intercalated by n-alkylamines with various chain lengths,
exposed to sonication in aqueous tetrabutylammonium hydroxide (TBAOH) and centrifuged to
separate the nanosheet-containing supernatant. The experiments included variations of a wide range
of conditions, which allowed for the achievement of impressive nanosheet concentrations in suspensions
up to 2.1 g/L and yields up to 95%. The latter were found to strongly depend on the length
of intercalated n-alkylamines. Despite the less expanded interlayer space, the titanates modified
with short-chain amines demonstrated a much higher completeness of liquid-phase exfoliation as
compared to those with long-chain ones. It was also shown that the exfoliation efficiency depends
more on the sample stirring time in the TBAOH solution than on the sonication duration. Analysis
of the titanate nanosheets obtained by means of dynamic light scattering, electron and atomic force
microscopy revealed their lateral sizes of 30–250 nm and thickness of 2–4 nm. The investigated exfoliation
strategy appears to be convenient for the high-yield production of perovskite nanosheet-based
materials for photocatalytic hydrogen production, environmental remediation and other applications.