High-throughput synthesis of multi-element alloy nanoparticles using solvothermal continuous-flow reactor

Abstract

High-throughput synthesis of multi-element alloy nanoparticles (MEA NPs) is essential for accelerating the discovery of advanced materials with complex compositions. Herein, we developed an automated continuous-flow reactor system capable of synthesising a wide variety of MEA NPs under controlled solvothermal conditions. The system operates at temperatures and pressures of up to 400 °C and 35 MPa, respectively, enabling the utilisation of supercritical fluids, such as supercritical water and ethanol, which broadens its synthetic applicability. The integrated automated precursor dispensing module is capable of preparing up to 20 distinct precursor sets from a library of 30 different metal sources, with each synthesis procedure requiring only 30 min for completion. A key throughput optimising feature is the parallel process execution, whereby precursor preparation and system cleaning are performed concurrently via the reactor heating, synthesis, and cooling cycles. All washing procedures, for both the precursor preparation module and reactor unit, are fully automated, further minimising downtime. Using this platform, we successfully synthesised MEA NPs containing combinations of d- and p-block metals, including high-entropy alloys. Structural analyses confirmed the formation of single-phase alloys, and in some cases, partial surface segregation of p-block elements was observed. Furthermore, we developed the direct one-step synthesis of supported MEA catalysts, such as RuRhPdIrPt/CeO₂. This study presents a scalable and versatile system for high-throughput MEA NP synthesis and offers a practical solution for bridging the gap between computational predictions and experimental materials development.