Water treatment is a priority health issue that scientists must address. In particular, in hospitals and the care sector, wastewater is polluted by medical products (antibiotics, anti-cancerous, anti-inflammatory or contraceptive drugs). Impact on the world’s population health is dramatic at short- and long-term, with eg. higher cancer risks and reduction of the human reproductive capacity, as treatments in place to date are not efficient enough. The development of novel sustainable cost-effective water treatment technologies is thus necessary. In this context, H2O2-driven photo-Catalytic Wet Peroxide Oxidation (CWPO) catalysis is a high-prospect advanced oxidation process operating under solar light for mineralizing those refractory compounds in water at room-temperature. Albeit very active, and although H2O2 is a green oxidant, producing only H2O and O2 as end-products, this catalysis still faces a limited perspective for technological deployment, that results from the use of costly and non-sustainably produced H2O2 instead of O2 as oxidant.
The aim of this master work, which is part of the CATLOC HiFunMat project, is to contribute to the development of a novel multi-functional catalysts for solar light-driven water treatment, by applying a strategy of catalytic (chemical) localism. This new concept proposes to combine two catalysts working in synergy under solar-light, the first one producing H2O2 from molecular water and O2, and the second one using H2O2 for degrading the pollutants. To do so, we will rely on the bottom-up layer-by-layer self-assembly to precisely control the spatial positioning of both catalysts and the resulting properties of the multilayer catalysts. The novelty here relies on the replacement of organic polyelectrolytes by inorganic polyelectrolytes, namely polyoxometalates, to improve the stability of films against self-oxidation issues, induced by the production of highly active oxidative radicals within the layers. The use of different building blocks (catalysts, polyelectrolytes), deposition methods and deposition conditions will allow exploring various assembly structures and determining those leading to the most relevant properties for our application. This work will be carried out in collaboration with ICPEES and BIOMAT labs.