New analytical approximation of feedback approach curves with a microdisk SECM tip and irreversible kinetic reaction at the substrate

International audienceAvailable approximate expressions used in the kinetic data treatment of (scanning electrochemical microscopy) SECM experiments in the case of steady-state feedback currents with irreversible reaction at the substrate and a microdisk tip are discussed. The necessity of new expressions is thus pointed out. A new expression of the current is then produced and discussed. It covers all usual experimental configurations (microdisks with Rg below 20, Rg characterizing the surrounding insulator thickness) and dimensionless tip-substrate distances larger than 0.1, with an accuracy of ±0.025 for any kinetics