Effect of K⁺ Force Fields on Ionic Conductivity and Charge Dynamics of KOH in Ethylene Glycol

Predicting ionic conductivity is crucial for developing efficient electrolytes for energy storage and conversion and other electrochemical applications. An accurate estimate of ionic conductivity requires understanding complex ion–ion and ion–solvent interactions governing the charge transport at the molecular level. Molecular simulations can provide key insights into the spatial and temporal behavior of electrolyte constituents. However, such insights depend on the ability of force fields to describe the underlying phenomena. In this work, molecular dynamics simulations were leveraged to delineate the impact of force field parameters on ionic conductivity predictions of potassium hydroxide (KOH) in ethylene glycol (EG). Four different force fields were used to represent the K+ ion. Diffusion-based Nernst–Einstein and correlation-based Einstein approaches were implemented to estimate the ionic conductivity, and the predicted values were compared with experimental measurements. The physical aspects, including ion-aggregation, charge distribution, cluster correlation, and cluster dynamics, were also examined. A force field was identified that provides reasonably accurate Einstein conductivity values and a physically coherent representation of the electrolyte at the molecular level

Chloride-Promoted High-Rate Ambient Electrooxidation of Methane to Methanol on Patterned Cu–Ti Bimetallic Oxides

The selective electrochemical methane oxidation reaction (MOR) has been challenging due to higher CH4 activation barriers and lower solubility at ambient conditions. Here, we synthesize a conductive gas-diffusion layer patterned with alternating squares of Cu and Ti oxides to achieve highly selective MOR at interfaces consisting of Cu–Ti bimetallic oxides. We observe high MOR faradaic efficiencies of ∼28% at ambient conditions and ∼72% at near-ambient conditions (40 °C) to value-added products such as CH3OH and HCOOH in a Cl–-mediated environment. Density function theory calculations suggest that despite TiO2 exhibiting barrierless thermochemical methane dissociation, an electrochemical oxidation pathway is likely competitive at high overpotentials. The unprecedented current densities of ∼10 mA/cm2 for HCOOH and ∼16 mA/cm2 for CH3OH, along with these insights on ambient MOR, will enable the development of highly efficient electrochemical systems for the utilization of CH4

Chloride-Promoted High-Rate Ambient Electrooxidation of Methane to Methanol on Patterned Cu–Ti Bimetallic Oxides

The selective electrochemical methane oxidation reaction (MOR) has been challenging due to higher CH4 activation barriers and lower solubility at ambient conditions. Here, we synthesize a conductive gas-diffusion layer patterned with alternating squares of Cu and Ti oxides to achieve highly selective MOR at interfaces consisting of Cu–Ti bimetallic oxides. We observe high MOR faradaic efficiencies of ∼28% at ambient conditions and ∼72% at near-ambient conditions (40 °C) to value-added products such as CH3OH and HCOOH in a Cl–-mediated environment. Density function theory calculations suggest that despite TiO2 exhibiting barrierless thermochemical methane dissociation, an electrochemical oxidation pathway is likely competitive at high overpotentials. The unprecedented current densities of ∼10 mA/cm2 for HCOOH and ∼16 mA/cm2 for CH3OH, along with these insights on ambient MOR, will enable the development of highly efficient electrochemical systems for the utilization of CH4