Interconversion of acid-base neutralization energy as electrical driving force can spontaneously desalinate saline water during electric power production without a net redox reaction. This entropically favorable chemistry performs desalination by reversible redox reactions involving only gases, water, H + , and OH À such that the products and reactants of the reaction will not contaminate the desalinated water.

The role of electrocatalysts in energy storage/conversion, biomedical and environmental sectors, green chemistry, and much more has generated enormous interest in comprehending their structure–activity relations. While targeting the surface-to-volume ratio, exposing reactive crystal planes and interfacial modifications are time-tested considerations for activating metallic catalysts; it is primarily by substitution in molecular electrocatalysts. This account draws the distinction between a substituent’s chemical identity and isomerism, when regioisomerism of the −NO2 substituent is conferred at the “α” and “β” positions on the macrocycle of cobalt phthalocyanines. Spectroscopic analysis and theoretical calculations establish that the β isomer accumulates catalytically active intermediates via a cumulative influence of inductive and resonance effects. However, the field effect in the α isomer restricts this activation due to a vanishing resonance effect. The demonstration of the distinct role of isomerism in substituted molecular electrocatalysts for reactions ranging from energy conversion to biosensing highlights that isomerism of the substituents makes an independent contribution to electrocatalysis over its chemical identity.

We utilize proton-coupled electron transfer in hydrogen storage molecules to unlock a rechargeable battery chemistry based on the cleanest chemical energy carrier molecule, hydrogen. Electrochemical, spectroscopic, and spectroelectrochemical analyses evidence the participation of protons during charge-discharge chemistry and extended cycling. In an era of anthropogenic global climate change and paramount pollution, a battery concept based on a virtually nonpolluting energy carrier molecule demonstrates distinct progress in the sustainable energy landscape.

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The interfacial electrochemistry of reversible redox molecules is central to state-of-the-art flow batteries, outer-sphere redox species-based fuel cells, and electrochemical biosensors. At electrochemical interfaces, because mass transport and interfacial electron transport are consecutive processes, the reaction velocity in reversible species is predominantly mass-transport-controlled because of their fast electron-transfer events. Spatial structuring of the solution near the electrode surface forces diffusion to dominate the transport phenomena even under convective fluid-flow, which in turn poses unique challenges to utilizing the maximum potential of reversible species by either electrode or fluid characteristics. We show Coulombic force gated molecular flux at the interface to target the transport velocity of reversible species; that in turn triggers a directional electrostatic current over the diffusion current within the reaction zone. In an iron-based redox flow battery, this gated molecular transport almost doubles the volumetric energy density without compromising the power capability.