Self-optimising continuous-flow hydrothermal reactor for nanoparticle synthesis

An autonomous continuous-flow, hydrothermal synthesis reactor, capable of self-optimising nanoparticle size using an in-line characterisation technique and machine learning is presented. The developed system is used for synthesis of hematite (α-Fe2O3) nanoparticles across three process variables, optimising for a target particle size. Optimisation is achieved in under 7 h with only 500 ml of 0.1 M Fe(NO3)3·9H2O aqueous stock solution used, and without human intervention.