A Method for Conducting Tafel Analysis

The application of linear, Tafel fitting procedures become problematic in the cases of experimental data featuring non-linearities in the Tafel (log(J)-V) response. This is especially difficult in low-overpotential regimes, where charge transfer kinetics generally control electrode behavior and Tafel analysis is expected to be most relevant. In response to this complication, and the qualitative forms of fitting that may arise from it, a methodology for the determination of Tafel slopes through a quantitative framework is presented. The efficacy of the method is tested using electrochemical measurements of well-characterized reactions for water splitting, hydrogen evolution and dioxygen reduction at iridium and platinum electrodes and shown to yield values consistent with literature reports of these catalysts. In addition, we show that the exchange currents extracted through this automated fitting procedure, used in conjunction with the Butler-Volmer model, are capable of reproducing the original electrochemical data in kinetically-controlled regimes for the cases of platinum-ORR and Iridium OER.