Operando Grazing Incidence X-Ray Diffraction and X-Ray Absorption Spectroscopy for Electrochemical CO2 Reduction on Aupd, Pd and Au Electrodes

The electrochemical reduction of carbon dioxide to fuels and chemicals using electricity produced from renewable sources represents an appealing approach to creating a carbon neutral fuel cycle or carbon negative chemical production pathway. However, a lack of fundamental understanding of the surface of the catalyst during electrochemical experiments hinders the development of more active catalysts. Recent reports indicate that the surface of the catalyst can change drastically under reducing conditions, suggesting that the active form may differ from the catalyst as characterized ex situ. Consequently, accurately probing the surface of the catalyst under operando conditions is critical to observing structural and electronic changes in the catalyst, allowing key insights into the carbon dioxide reduction reaction. We report the design and development of such operando experiments at the Stanford Synchrotron Radiation Lightsource using grazing incidence x-ray diffraction and grazing incidence x-ray absorption spectroscopy. Using these techniques, we study changes in the surface physical and electronic structure of thin film Au, Pd, and AuPd catalysts during electrochemical carbon dioxide reduction.