Development of a spectroelectrochemistry assembly (SNIFTIRS) based on a commercial spectrophotometer. Test with the ferrocyanide/ferricyanide redox couple

The development of a spectroelectrochemistry assembly for substractively no rmalized interfacial FTIR spectroscopy (SNIFTIRS), based on the commercial spectrophotometer Unicam Research Series 1, is presented. The sample chambe r has been modified to achieve a vertical orientation of the cell and a spe cial support was constructed for the same purpose. The original path of the IR radiation has been modified by using two black anodized aluminium 30 de grees wedges, both supporting a parabolic mirror. This allows the radiation to reach the working electrode forming 60 degrees with the vertical. The c ell holder allows vertical and horizontal displacement of the cell. The ele ctrochemical cell was made of Pyrex glass and permits an easy manipulation even in the sample chamber of the spectrometer, making it unnecessary to op en this chamber in the manipulation of either the solution or the electrode s. The working electrode was a polished polycrystalline gold electrode. A c omputer-based potentiostat was also constructed. To control the system, a s et of 16-bits Visual-Basic programs was developed allowing the synchronizat ion between the spectra acquisition and the application of potentials. A va riety of sequences of operation can be selected. The system was checked wit h the ferrocyanide/ferricyanide redox couple, concluding that the system he re described is useful to make SNIFTIRS experiments, being versatile enough to design new operational sequences that help improve the knowledge of the electrode processes.