Interfacial pH Measurements Using a Rotating Ring?Disc Electrode with a Voltammetric pH Sensor

Electrochemical reactions in which H+ or OH? ions are produced consumed, affect the pH near electrode surface. Probing locally is therefore highly desired to understand and model reaction environment under operando conditions. We carried out interfacial measurements mass transport control using a rotating ring-disc (RRDE) coupled with our recently developed voltammetric sensor. The disc detected by functionalizing gold ring hydroxylaminothiophenol (4-HATP)/4-nitrosothiophenol (4-NSTP) redox couple. As protons only have interact monolayer containing 4-HATP/4-NSTP, sensitivity time resolution that can be achieved superior potentiometric sensors. used hydrogen evolution as performed buffered unbuffered electrolytes. effects of current density, potential, buffer capacity electrolyte rotation rate on local were investigated. This work shows reliable sensitive method for accurately probing well-defined conditions, over wide range.