How Buffers Resist Electrochemical Reaction-Induced pH Shift under a Rotating Disk Electrode Configuration.

In mild acidic or alkaline solutions with limited buffer capacity, the pH at the electrode/electrolyte interface (pH) may change significantly when the supply of H (or OH) is slower than its consumption or production by the electrode reaction. Buffer pairs are usually applied to resist the change of pH during the electrochemical reaction. In this work, by taking HX ⇄ 2H + X + 2e under a rotating disk electrode configuration as a model reaction, numerical simulations are carried out to figure out how pH changes with the reaction rate in solutions of different bulk pHs (pH in the range from 0 to 14) and in the presence of buffer pairs with different p values and concentrations.