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Project Code [2024-HE-1274]

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Project title

Deep Eutectic Solvents for Inorganic Green Nanomaterials

Primary Funding Agency

Environmental Protection Agency (EPA)

Co-Funding Organisation(s)

n/a

Lead Organisation

University of Dublin, Trinity College (TCD)

Lead Applicant

Peter Dunne

Project Abstract

Inorganic nanomaterials, with their proven benefits in catalysis, low-energy devices, and renewable energy technologies have a crucial role to play in the development of a greener society. Key factors in determining the properties and performance of these materials include their composition, crystalline phase, and morphology (size and shape). Established synthetic routes to inorganic nanomaterials capable of this control require expensive, volatile, and environmentally hazardous organic solvents, complex and costly precursors, and auxiliary chemicals or employ hazardous high pressures and specialised equipment. The deployment of nano-enabled technologies in an economically-viable, environmentally benign, and sustainable way thus requires new, green, synthetic routes to these functional nanomaterials. Deep Eutectic Solvents (DES) have recently emerged as green alternatives to conventional organic solvents, particularly in organic synthesis and extraction. DES are mixtures of two or more (solid) molecular components, with intermolecular interactions causing a depression in the melting point of the mixture, allowing access to novel liquid phases. The components of a DES are hydrogen bond acceptors (HBAs) and hydrogen bond donors (HBDs). These include alkylammonium halides and simple metal salts as HBAs, and compounds such as urea, glycerol, or menthol as HBDs. Many of these components are widely available from natural sources, leading to so-called natural deep eutectic solvents, or NADES. The nature of the component HBAs/HBDs and their interactions results in DES exhibiting a wide range of properties which both align them with the key principles of green chemistry, and make them highly attractive for nanomaterial synthesis. In green chemistry terms, these properties include their abundant, natural, and renewable sources; low volatility, making for safer, less hazardous syntheses and processes; biocompatibility and biodegradability, addressing end-of-life concerns. DES further have low surface tension, high viscosities, and potential to act as capping and templating agents. These properties are highly tuneable based on DES composition, and strongly influence nucleation and growth behaviour for the size- and shape-controlled generation of nanomaterials. Here we will target the DES-mediated production of two environmentally relevant classes of inorganic nanomaterials: i) photoelectrocatalytic metal oxides for pollutant degradation and hydrogen generation, and ii) nanophosphors for low-energy solid-state lighting. i) will focus on the synthesis of titanium oxide-based materials — prototypical photoelectrocatalysts. These materials are well known with key property-determining factors of crystallographic phase, particle size, and shape; each expected to be highly impacted by choice of DES components. This will expand to doped titanium oxides and related mixed metal oxide perovskites, adding further scope and complexity to the DES-synthesised materials. ii) will establish routes to rare-earth doped phosphate nanophosphors, with uses in low energy lighting as components of white-light LEDs. This class of material is significantly less explored; but are of great interest as they offer the potential to replace current generation mercury-containing compact fluorescent lights. DES properties and tuneability are expected to offer enormous advantages in the successful incorporation of luminescent rare-earth dopant ions into the host phosphate structure. This project will thus show that cleaner, greener deep eutectic solvents offer viable, sustainable routes to environmentally relevant functional nanomaterials.

Grant Approved

€657,285.80

Research Hub

Delivering a Healthy Environment

Research Theme

Chemicals that are safe and sustainable by design

Start Date

31/03/2025

Initial Projected Completion Date

30/03/2029