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Shuttling protons in ammonia synthesis An electrochemical route to ammonia could substantially lower the greenhouse gas emissions associated with the current thermal Haber-Bosch process. One relatively promising option under study involves reductive formation of lithium nitride, which can be protonated to ammonia. However, the ethanol used to date as a local proton source in these studies may degrade under the reaction conditions. Suryanto et al. report the use of a tetraalkyl phosphonium salt in place of ethanol (see the Perspective by Westhead et al. ). This cation can stably undergo deprotonation–reprotonation cycles and, as an added benefit, it enhances the ionic conductivity of the medium. Science , abg2371, this issue p. 1187 ; see also abi8329, p. 1149

The development of safer electrolytes is critical for the advancement of electrochemical energy storage applications. Ionic Liquids (ILs) and Organic Ionic Plastic Crystals (OIPCs) are attractive choices as electrolytes due to their high thermal stabilities and intrinsic ionic conductivities. However, fundamental understanding of the impact of cation and anion choice, to form ILs or OIPCs, is still lacking, particularly with regard to how this can affect the electrolyte properties. In this work, we explore the synthesis and characterisation of several oxazolidinium-based salts to understand the effect of the ether functional group in the cation ring. Specifically, we investigate the 3,3-dimethyloxazolidinium ([C1moxa]+) cation, paired with dicyanamide ([DCA]−), bis(fluorosulfonyl)imide ([FSI]−), bis(trifluoromethanesulfonyl)imide ([TFSI]−), tetrafluoroborate ([BF4]−) and hexafluorophosphate ([PF6]−) anions. In addition to investigating the influence of the anion, the effect of changing the cation side chain is examined with 3-ethyl-3-methyloxazolidinium bis(fluorosulfonyl)imide ([C2moxa][FSI]). Studies of thermal behaviour revealed that these oxazolidinium-based salts can be highly disordered and exhibit wide phase I temperature ranges. The transport properties of the salts were determined by examining the ionic conductivity, ion dynamics using solid-state Nuclear Magnetic Resonance (NMR) analysis, and the free volume through Positron Annihilation Spectroscopy (PALS). It was found that oxazolidinium-based salts exhibit faster ion transport than the equivalent pyrrolidinium-based salts, which is consistent with the larger free volume. Hence, oxazolidinium-based salts demonstrate scope as promising electrolytes for battery applications due to their high ionic conductivity and good thermal and electrochemical stability.

Electrochemical ammonia synthesis at ambient temperature and pressure shows promise as a route to a carbon-free chemical fuel for renewable energy transportation and storage. However, before this p...

Renewable energy-driven ammonia electrosynthesis by N2 reduction reaction (NRR) at ambient conditions is vital for sustainability of both the global population and energy demand. However, NRR under ambient conditions to date has been plagued with a low yield rate and selectivity (

The reduction of 2,4,6-trinitrotoluene (TNT) has been studied in eight room temperature ionic liquids (RTILs) on a gold (Au) microdisk electrode and a Au thin film electrode (TFE). Three reduction peaks were observed in all RTILs, corresponding to the reductions of each of the three nitro groups in the TNT structure. TNT was the easiest to reduce in imidazolium RTILs, followed by pyrrolidinium and then tetraalkylphosphonium. Diffusion coefficients (D) and electron counts (n) were calculated from potential-step chronoamperometry on the first reduction peak. D’s ranged from 0.7 × 10–11 to 4.1 × 10–11 m2 s–1, and a plot of D against the inverse of viscosity was linear, indicating that the Stokes–Einstein relation holds well for TNT in RTILs. The electron count was one in most RTILs—in stark contrast to the widely accepted six-electron reduction in protic solvents. An electrogenerated red solid was formed after the first reduction peak, believed to be an azo (or azoxy) compound formed by dimerization of two T...