Chemical rules for the design of iron, boron and phosphorus-based compounds in molten salts for electrocatalytic water splitting

This proposal aims at discovering new electrocatalyst materials by probing in situ chemical reactions in inorganic liquids, ie. molten salts. Based on machine learning to identify a priori the composition ranges most likely to provide new compounds, we will target solids made of Earth-abundant elements Fe, B and P and of interest for electrocatalytic water splitting. Molten salts enable reactions at 300-1000 °C and offer a chemical space to explore thanks to a parameter never considered before: the chemical hardness of the solvent anions, by adjusting molten salt mixtures. This sets the stage for the discovery of new materials compared to traditional methods. We will use in situ time-resolved X-ray diffraction and in situ total X-ray scattering coupled to PDF analysis to identify reaction intermediates and new solids. The reaction conditions identified in situ will then be used in our lab to isolate these solids, which will deliver new materials for electrocatalysis.