(521bg) A Deep Dive into Dynamic Catalysis: The Impact of Potential Modulation on Formic Acid Electro-Oxidation Efficiency

Formic acid has garnered attention due to its capacity to store hydrogen in larger quantities, resulting in a higher energy density and a safer transportation alternative. Previous research on platinum-catalyzed electro-oxidation of formic acid has shown that applied potential oscillations can yield rates up to ~20 times higher than the maximum static conditions. In this work, we examined the effects of potential oscillations on faradaic and thermodynamic efficiency and the impact of the duty cycle (time spent at each potential) on the rate of CO₂ formation. The potential oscillations were applied from 0 V to 0.8 vs NHE in a square-wave form. Kinetic and electrochemical measurements revealed that oscillations do not significantly impact faradaic efficiency but increase thermodynamic efficiency relative to static conditions. The duty cycle significantly influences the CO₂ formation rate, with the maximum rate achieved at a 95% (0.8 V vs NHE) duty cycle. However, a thermodynamic efficiency penalty is associated with the duty cycle, which defines the limitations of dynamic potential modulation that balance energy efficiency and rate. Optimum conditions can be established based on the importance assigned to the kinetic and thermodynamic parity conditions and the available resources considered. When the thermodynamic efficiency is set equal to the static maximum when energy conservation is vital, the CO₂ formation rate is enhanced approximately 10 times higher. On the other hand, when the rate is set equal to the static maximum when maximizing production is important, the thermodynamic efficiency increases approximately three times higher.