A practical grand canonical framework for electrocatalytic modelling with potential-dependent interfacial thermodynamics

As interest in nanomaterials grows, ab initio simulations play a crucial role in designing electrochemical catalysts. Electrochemical reactions depend on electrode potential, highlighting the importance of the grand canonical representation, where the number of electrons can be adjusted in the electrode. The Grand Canonical Density Functional Theory (GC-DFT) offers accuracy and computational efficiency, while the Grand Canonical Potential–Kinetics (GCP-K) method provides a broadly applicable quantum-mechanical approach for investigating electrocatalytic mechanisms and kinetics. In this work, we introduce the generalized Grand Canonical Potential (g-GCP-K) method, which improves the GCP-K framework by achieving accuracy comparable to GC-DFT while retaining its versatility. The efficiency of the g-GCP-K method is demonstrated through calculations of surface charge density and differential capacitance for graphene. Furthermore, we highlight the importance of rigorous evaluation of thermodynamic stability in reaction intermediates during the electrochemical reduction of carbon dioxide on copper-doped graphitic carbon nitride catalyst. Our analysis reveals that potential-dependent electrochemical properties significantly influence reaction thermodynamics, thus affecting the stability of key intermediates.