In situ grazing-incidence X-ray diffraction during electrodeposition of birnessite thin films: Identification of solid precursors

Abstract A special electrochemical flow-cell allowing in situ grazing-incidence X-ray diffraction during electrodeposition of thin films has been successfully developed. This original setup is very simple and permits characterisations by reflection onto large surfaces by using an X-ray transparent window used also as a counter electrode. This cell was tested by studying the electrodeposition of birnessite thin films as a function of background electrolytes. In Na 2 SO 4 solution, buserite was identified as the only in situ solid precursor. Its dehydration into birnessite was monitoring in real time and was complete in few minutes. In K 2 SO 4 aerated solution, birnessite was electrodeposited directly as very small crystals. This demonstrates the usefulness of this electrochemical flow-cell for characterising compounds during electrochemical measurements.