Development of a high pressure stirring cell up to 2 GPa: a new window for chemical reactions and material synthesis

Abstract

A new method for stirring under high pressure conditions has been developed and tested. The key component is a Teflon cell assembly equipped with magnetic stirring function, which is capable to operate across a wide pressure range, up to at least 2 GPa, in a large volume press. The setup enables adjustable stirrer rotation rate and detection of stirring in a sample, e.g. to observe liquid–solid phase transitions at high pressure. The viscosity limit of stirring is ca. 500 times that of water at room temperature (i.e. ∼500 mPas). Moreover, we show that zinc oxide nanoparticles hydrothermally synthesized at 0.5 GPa and 100°C under stirring conditions show an order of magnitude smaller size (100 nm) compared to those synthesized under non-stirring conditions (1 μm). The wide pressure range for stirring of viscous media opens interesting possibilities to produce novel materials via hydrothermal synthesis and chemical reactions.