Thermoneutrality Is Not Necessary to Maximize Oxygen Evolution Reaction Rates

Area of Science:

• Electrocatalysis
• Surface Chemistry
• Reaction Kinetics

Background:

• Optimizing binding energies of reaction intermediates is key to electrocatalytic activity.
• Thermoneutral energy landscapes are often considered ideal for minimizing overpotential.
• Scaling relationships pose challenges to achieving thermoneutrality in oxygen evolution reaction (OER) catalysts.

Purpose of the Study:

• To investigate whether thermoneutrality is essential for maximizing oxygen evolution reaction (OER) rates.
• To explore the impact of non-thermoneutral energy landscapes on catalytic performance.
• To determine the theoretical limits of OER catalyst activity.

Main Methods:

• Development of a microkinetic model incorporating acid-base and direct-coupling mechanisms.
• Numerical simulations to analyze reaction rates under varying binding energy conditions.
• Comparison of catalytic rates for thermoneutral and non-thermoneutral catalyst designs.

Main Results:

• Thermoneutrality is not a prerequisite for maximizing OER rates.
• Non-thermoneutral catalysts can achieve rates comparable to thermoneutral ones.
• Tuning binding energies to provide driving force for kinetically unfavorable steps enhances rates, but diminishes reverse reaction rates.

Conclusions:

• Achieving high OER rates in one direction does not necessitate a thermoneutral energy landscape.
• Thermoneutrality is required to maximize rates in both forward and reverse directions.
• Catalyst design can prioritize unidirectional rate enhancement over overall reversibility.