An exploration of Silsesquioxanes and Zeolites using High-Speed experimentation

Combinatorial Chemistry and High-Speed Experimentation techniques allow the rapid preparation and testing of large numbers of samples by using automated workstations. These techniques are increasingly applied to various fields of chemical research and particularly to catalysis. In this project, High-Speed Experimentation techniques were used to study two families of compounds with a silicon-oxygen framework: silsesquioxanes and zeolites. Silsesquioxanes are inorganic-organic hybrid materials with broad applications as model compounds for silica surfaces and as ligands in coordination chemistry and catalysis. Here, the synthesis of incompletely condensed silsesquioxanes as precursors for titanium catalysts active in the epoxidation of alkenes was optimised by means of High-Speed Experimentation techniques. This thorough study led to the identification of a number of trends, to new and more efficient methods to synthesise known silsesquioxanes and to the discovery of new silsesquioxane precursors for active catalysts. The most interesting results were reproduced at a conventional laboratory scale and the silsesquioxane products were fully characterised. One of these silsesquioxane structures was used to prepare an osmium complex that proved to be a useful model compound for a known heterogeneous catalyst and an active and safe homogenous catalyst for the dihydroxylation of alkenes. Zeolites are microporous crystalline materials with applications as heterogeneous catalysts, ion-exchangers and molecular sieves. The synthesis of aluminium-rich zeolite beta was investigated by means of High-Speed Experimentmation techniques in order to identify the lowest Si/Al ratio to obtain pure zeolite beta with hydrothermal methods.Applied Science

High-performance membranes with full pH-stability

International audienceFollowing current strong demands from, among others, paper, food and mining industries, a novel type of nanofiltration membrane was developed, which displays excellent performance in terms of selectivity/flux with a unique combination of chemical stability over the full (0-14) pH-range and thermal stability up to 120 °C. The membrane consists of polyvinylidene fluoride grafted with polystyrene sulfonic acid. The optimum membrane showed water permeances of 2.4 L h-1 m-2 bar-1 while retaining NaCl, MgSO4 and Rhodamine B (479 Da) for respectively ≈60%, ≈80% and andgt;96%. © 2018 The Royal Society of Chemistry

Innovative and functional materials for green and safe Na-ion large-scale energy storage

The modern life style that we are enjoying depends on energy storage systems in which the role of Li-ion batteries (LiBs) is peerless. However, state-of-the-art LiBs are approaching the verge of possible technological imagination in energy density. Some researchers argue that next-gen secondary batteries should switch to heavier elements such as Na. Indeed, when it comes to gigantic energy storage systems for the electricity grid and/or other non-portable applications where size does not matter, Na-ion batteries (NiB) can be an intelligent choice. Nevertheless, research on NiBs' components is at the very beginning, and it is necessary to develop novel types of materials, both novel high energy electrodes and stable and safe polymer electrolytes. In this work, an overview is provided on both truly solid and quasi-solid polymer electrolytes specifically conceived and developed for Na-ion secondary cells, based on polyethylene oxide (PEO), acrylates/methacrylates and/or mixtures thereof. Eventually, pyranose ring based natural additives and/or low volatile plasticizers are added along with supporting sodium salts to improve specifically defined characteristics. Both standard casting and smart photopolymerization techniques have been explored. Moreover, the most recent results regarding novel nanostructured negative electrodes, comprising TiO2 nanotubes, Ga2O3 nanorods and graphene-supported metal oxides will be presented. So far, work on Na-ion polymer batteries for moderate temperature application is at an early stage, only lab-scale small battery cells are demonstrated. The results about Ga2O3 nanorods and TiO2 nanotubes, along with the appropriate choice and development of novel polymer electrolytes, demonstrate that safe, durable and high energy density secondary Na-based polymer devices conceived for green-grid storage and operating at ambient and/or sub-ambient temperatures can be a reality in the near futur