Geo-inspired pathways towards nanoparticle-based metastable solids

ended

Constant search of new solids is required to advance our knowledge in materials science, and then to stimulate progresses in fields like energy and environment. Genesis aims at expanding the collection of functional inorganic solids as nanoparticles by rational exploratory synthesis. The pivotal idea is to draw inspiration from the processes of solid formation encountered in natural geological processes, in order to set a framework of synthesis conditions prone to yield new nanoscaled solids. I focus on kinetically stabilized, metastable solids, which yield novel, sometimes surprising properties prone to deliver new functions. However, conventional solid-state syntheses use high temperatures that yield thermodynamic products, hence hampering the synthesis of metastable inorganic solids. This obstacle is even more significant when the solids possess complex structures, as is the case of non-oxides made of transition metals and boron, silicon or phosphorus. The known members of these families are made of covalent bonds that bring unique electrocatalytic properties. This motivates the search of ternary solids joining these elements. Their quest is a synthetic challenge that I will address by the discovery of new metastable covalent solids. To do so, I will set an original inorganic synthesis methodology by taking inspiration from the processes of crystallization of gems in molten salts, of lavas at high rate and of metamorphic rocks at high pressures to merge nanosciences and solid-state chemistry. Genesis will operate at the crossroad of three pillars: use of the surface energy of nanoparticles to stabilize solids that would be metastable in their extended form; establishment of liquid-phase syntheses at 300-1000 °C in mild conditions; use of high-pressure chemistry to stabilize new solids. Within this frame, I will develop new methods to screen in situ the reaction pathways and I will trigger a new reactivity between boron, silicon, phosphorus and nanoparticles.