HIGH ENTROPY HYDROXIDES FOR WATER CLEANING AND SPLITTING INTO OXYGEN AND HYDROGEN

Work package:
Water sanitation is one of the major challenges facing our society, particularly in rural areas of developing countries. The chemical photodegradation of polluting compounds allows for the purification of our vital resource. Simple compounds such as TiO2, ZnO, or BiVO4 have proven their capacity for chemical transformation, but the absorption of solar energy is often limited to the UV range, resulting in moderate effectiveness. Furthermore, these compounds are less reactive with certain pollutants due to their (micro)structures and physicochemical properties. Compounds such as hydrated talc, derived from abundant natural resources, are promising for this eco-sustainable photochemical conversion goal. Layered Double Hydroxides (LDH) or 2-dimensional materials, offer a wide variety of chemical compositions and a large specific surface area, giving them broad accessibility to volatile gases and chemical molecules that are problematic for our environment1. However, they are poor conductors of charges, which is essential for chemical reactivity, and their solar spectrum absorbance must be broadened to increase conversion efficiency. In this context, the preparation of nano- or micro-particles of LDH compounds from common metallic elements (FeAl, CuAl, MgFe, etc.) are key objectives for expanding their uses. High entropy hydroxide (HEH) nano-materials would not only allow to adjust their band gap and light-absorption but also facilitate charge transport2,3. Indeed, these new types of materials, based on a cocktail effect that stabilizes original compounds due to an equivalent proportion of at least 5 abundant metal elements, will represent an innovative and promising solution for the photodecomposition of pollutants in water and/or water splitting in order to produce H2 gas, this latter being an essential energy vector for various stationary and transport technologies… This Master project will focus on the synthesis and study of nano- and micro-powders of HEH. Soft chemistry methods will be used in order control the shape and size of particles. Their structural and microstructural properties will be studied by using XRD, SEM, TEM, spectroscopy techniques…, in relationships with their optical, electrochemical and photocatalytic properties. Applications are related to Environment, Social and Energy domains. This work will be conducted at the CIRIMAT lab. and University of Toulouse, in a high-quality scientific environment.