A flow cell designed for in situ/operando observation of electrocatalyst surfaces by attenuated total reflection infrared spectroscopy

Spectroscopic observations of the intermediates formed on the electrode surfaces are essential for understanding the catalytic mechanism to overcome its activation barrier but are often hampered by the bubble formation on the electrode during the reaction. To solve this issue, we have designed a new flow cell for in situ attenuated total reflection infrared (ATR-IR) spectroscopy by introducing a genuine function in the electrode to eliminate gas bubbles from the electrode surface. The flow cell for the in situ ATR-IR (ATR-Cell) measurement consists of two compartments. One compartment, where a working electrode is located, has multiple flow paths, allowing liquid and gas to be fed separately to the working electrode for use in future operando observations. We have demonstrated in situ observation of the intermediates on IrO2 in the oxygen evolution reaction of water electrolysis and on Cu nanoparticles in the CO2 reduction reaction using ATR-Cell.