Alkene hydrosilylation with supported and unsupported Ni nanoparticles: strong influence of the Ni environment on activity and selectivity

Owing to the high-volume production of the silicone industry, in which hydrosilylation products are polluted by Pt, it is of major interest to develop alternative catalysts that would be based on non-noble metals and that would be easy to separate from the reaction products. In this context, we explore here the preparation of catalysts based on non-noble metal nanoparticles as alternatives to Pt complexes or non-noble metal complexes (main trend in academic research). We demonstrate here that isolated nickel nanoparticles in solution or deposited on silica can be used as catalysts for alkene hydrosilylation. The composition of the nickel nanoparticles (nickel silicide, metallic nickel or nickel oxide) is key for selectivity and activity. These catalysts which exhibited similar Ni particle sizes were tested in the challenging reaction of triethoxysilane with triethoxyvinylsilane. The heterogeneous catalyst based on metallic nickel nanoparticles was found to be the most promising and could be filtered off, leading to pure reaction products (no metal pollution). This result suggests that the exploration of non-noble metal nanoparticles and particularly diverse nickel (0) phases may be a key to the development of highly selective heterogeneous catalysts. Isolated nickel nanoparticles in suspension or supported on silica are efficient catalysts for inactivated alkene hydrosilylation.