Temperature-Dependent Redox Thermodynamics in Emerging Electrochemical Systems: From Magnetohydrodynamic Hydrogen Production to CO₂-to-Chemicals Manufacturing
Journal Article
Overview
abstract
Electrochemical technologies are increasingly viewed as foundational tools for low carbon chemical manufacturing because they allow redox transformations to be driven directly by renewable electricity rather than by thermal energy. Two emerging applications, magnetohydrodynamic electrolysis for hydrogen production and redox enabled carbon capture, illustrate how temperature dependent redox thermodynamics influence the efficiency and scalability of electrified chemical processes. However, the temperature sensitivity of many important electrochemical reactions is still not well quantified, which limits the predictive design of next generation manufacturing systems. This work presents an integrated experimental and computational study that examines how temperature affects electrochemical reaction energetics central to both hydrogen production and carbon dioxide derived chemical manufacturing. In the case of magnetohydrodynamic electrolysis, we investigate how convection generated by Lorentz forces alters the temperature dependence of the hydrogen evolution reactions. Variable temperature electrochemical measurements show that enhanced mass transport increases the temperature sensitivity of kinetic parameters and shifts the balance between activation controlled and diffusion controlled behavior. These results emphasize the need for accurate temperature dependent thermodynamic inputs when designing magnetohydrodynamic reactors for renewable hydrogen manufacturing. In parallel, we study temperature effects in redox enabled carbon dioxide capture systems in which molecular sorbents bind carbon dioxide in their reduced state and release it upon oxidation. Quinone based sorbents serve as a model platform for electrified carbon dioxide upgrading because their reduced forms act as nucleophiles that form reactive carbon dioxide adducts which can serve as intermediates for downstream chemical manufacturing. Variable temperature cyclic voltammetry shows that both the quinone reduction potential and the carbon dioxide binding step display stronger temperature dependence than predicted by simple Nernstian approximations. Comparisons with density functional theory calculations reveal systematic deviations that arise from entropic penalties and solvation effects, highlighting the need for improved thermodynamic models for electrified carbon to chemicals pathways. Taken together, these studies show that temperature exerts a broad influence on electrochemical systems by affecting intrinsic redox energetics, coupled chemical reactivity, and mass transport. By quantifying these effects across hydrogen production and carbon dioxide derived chemical manufacturing, this work provides a foundation for the design of efficient electrified chemical processes with improved predictive control.
