First-order Reversal Curve Analysis of Phase Transitions in Electrochemical Adsorption: A New Experimental Technique Suggested by Computer Simulations

The first-order reversal curve (FORC) method for analysis of systems undergoing hysteresis is applied to dynamical models of electrochemical adsorption. In this setting, the method can not only differentiate between discontinuous and continuous phase transitions, but can also quite accurately recover equilibrium behavior from dynamic analysis for systems with a continuous phase transition. Discontinuous and continuous phase transitions in a two-dimensional lattice-gas model are compared using the FORC method. The FORC diagram for a discontinuous phase transition is characterized by a negative (unstable) region separating two positive (stable) regions, while such a negative region does not exist for continuous phase transitions. Experimental data for FORC analysis could easily be obtained by simple reprogramming of a potentiostat designed for cyclic-voltammetry experiments.