Since their conception, ionic liquids (ILs) have been investigated for an extensive range of applications including in solvent chemistry, catalysis, and electrochemistry. This is due to their designation as designer solvents, whereby the physiochemical properties of an IL can be tuned for specific applications. This has led to significant research activity both by academia and industry from the 1990s, accelerating research in many fields and leading to the filing of numerous patents. However, while ILs have received great interest in the patent literature, only a limited number of processes are known to have been commercialised. This review aims to provide a perspective on the successful commercialisation of IL-based processes, to date, and the advantages and disadvantages associated with the use of ILs in industry.

Spiky/hollow metal nanoparticles have applications across a broad range of fields. However, the current bottom-up methods for producing spiky/hollow metal nanoparticles rely heavily on the use of strongly adsorbing surfactant molecules, which is undesirable because these passivate the product particles’ surfaces. Here we report a high-yield surfactant-free synthesis of spiky hollow Au–Ag nanostars (SHAANs). Each SHAAN is composed of >50 spikes attached to a hollow ca. 150 nm diameter cubic core, which makes SHAANs highly plasmonically and catalytically active. Moreover, the surfaces of SHAANs are chemically exposed, which gives them significantly enhanced functionality compared with their surfactant-capped counterparts, as demonstrated in surface-enhanced Raman spectroscopy (SERS) and catalysis. The chemical accessibility of the pristine SHAANs also allows the use of hydroxyethyl cellulose as a weakly bound stabilizing agent. This produces colloidal SHAANs that remain stable for >1 month while retaining the functionalities of the pristine particles and allows even single-particle SERS to be realized.

During this work, an original study of the CO2 and SO2 competitive gas absorption in three superbase ionic liquids, namely trihexyltetradecylphosphonium 1,2,4-triazolide ([P66614][124Triz]) and trihexyltetradecylphoshonium benzimidazolide ([P66614][Benzim]), is reported for the first time. To initiate such a comprehensive study, the CO2 and SO2 mixed gas solubility in selected ILs was determined by using an original and accurate dynamic method coupled with a mass spectrometer after several absorption and desorption cycles. This method has been validated by comparing the gravimetric uptake of CO2 with the mass spectrometry data using trihexyltetradecylphosphonium benzotriazolide, 1,2,4-triazolide and benzimidazolide ionic liquids and shown to be consistent within 10 % in mole ratio units. Solubility results clearly show that the presence of SO2 in the gas stream decreases the CO2 capture capability of the investigated ILs. Furthermore, the viscosity, chemical analysis (water content and sulfur content) and spectroscopic data (1H-NMR, 13C-NMR, ATR-IR and XPS) changes before and after absorption/desorption of the gases were determined and depicted to truly understand the reaction mechanism which occurs in the liquid phase highlighting a clear competition between the SO2 vs. CO2 chemical reaction and selected superbase ILs.

Ionic liquids were shown to have a potential for simultaneous separation and recycling of plastics from multicomponent waste streams.

Carbon Capture and Utilization (CCU) presents a great opportunity. CO ₂ can be electrocatalytically converted to formate. The subsequent formate to oxalate coupling reaction (FOCR), which has been studied for two centuries, is critically discussed.