Fig. 1. Schematic representation of the cell used for electrochemical and attenuated total reflectance (ATR)-IR spectroelectrochemical measurements on nitrogenase MoFe protein. A Pt wire counter electrode and a miniature saturated calomel reference electrode14 were inserted into buffered electrolyte solution in contact with a carbon paper working electrode pressed against a carbon rod connector. Protein was trapped in a Nafion–Tris layer between the working electrode and the ATR internal reflection element. Inset: cross section of the working electrode construction. Experimental details are provided in the ESI.† .
