Deep Eutectic Solvents in Nanomaterial Synthesis

Deep eutectic solvents (DES) are designer liquids formed from a hydrogen-bond donor and acceptor that exhibit melting-point depression and unique solvent properties. They offer tunable polarity, negligible vapour pressure, biodegradability and low toxicity. In nanomaterial synthesis, DES serve simultaneously as reaction medium, structure-directing agent, reducing and stabilising agent and green template. Their inherent supramolecular networks can modulate precursor speciation, nucleation kinetics and crystal growth, enabling precise control over particle size, morphology and surface functionality under mild conditions. Applications span the synthesis of metal and metal oxide nanoparticles, carbon-based nanostructures and hybrid composites, with impacts in catalysis, biomedicine, energy conversion and environmental remediation. By reducing energy demands and eliminating hazardous reagents, DES-mediated routes are transforming sustainable nanomanufacturing on a global scale.

Research from Nature Portfolio

Recent studies have elucidated the deep eutectic-solvothermal synthesis of nanostructured ceria using a choline chloride–urea mixture. This work demonstrates how the DES acts as a latent supramolecular catalyst: its hydrogen-bond network pre-organises cerium precursors and accelerates oxide formation at significantly lower temperatures than conventional hydrothermal methods. Detailed liquid-phase neutron diffraction revealed molecular-scale mechanisms by which solvent-driven pre-organisation enhances reaction rates. Control of porosity and morphology was achieved through simple alteration of DES composition, paving the way for scalable, low-energy manufacture of ceria with improved oxygen storage capacity and catalytic activity.

Deep Eutectic Solvents in Nanomaterial Synthesis publication trend

The graph below shows the total number of articles in deep eutectic solvents in nanomaterial synthesis across all publications each year (not limited to Nature Index journals).

Technical terms

Deep eutectic solvent (DES): A mixture of a hydrogen-bond donor and acceptor exhibiting a melting point lower than its individual components, used as a green solvent.

Solvothermal synthesis: A method of nanomaterial production in which reactions occur in a solvent at elevated temperature and pressure within a sealed vessel.

Reline: A common DES composed of choline chloride and urea in a 1 : 2 molar ratio, used as both reducing and stabilising medium.

Natural deep eutectic solvent (NDES): A DES whose constituents are derived from natural, often biocompatible, sources such as sugars and organic acids.

Supramolecular catalysis: Catalytic enhancement arising from non-covalent interactions within organised molecular assemblies such as DES hydrogen-bond networks.

References

1. Role of the Deep Eutectic Solvent Reline in the Synthesis of Gold Nanoparticles. ACS Sustainable Chemistry & Engineering (2023).
2. Perspectives for the use of deep eutectic solvents in the preparation of electrochemical sensors and biosensors. Current Opinion in Electrochemistry (2024).
3. Deep eutectic-solvothermal synthesis of nanostructured ceria. Nature Communications (2017).
4. Natural Deep Eutectic Solvents in the Synthesis of Inorganic Nanoparticles. Materials (2023).