Design, preparation and characterization of aerogel NiO–CuO–CoO/SiO2 nanocomposite as a reusable catalyst for C–N cross-coupling reaction†
Aerogels are porous, non-crystalline solid materials with high specific surface space, plentiful three-dimensional (3D) porous construction, ultra-low density and significant porosity. The aerogel nanocomposite is produced using sol–gel and supercritical drying processes. CO2 supercritical drying (SCD) is the most powerful process, ensuring optimal product properties such as high porosity, low density, and high thermal conductivity. On this account, we used the CO2 supercritical drying method to produce NiO–CuO–CoO/SiO2 nanocomposite aerogels and applied it as a reusable catalyst for the C–N cross-coupling reaction (Buchwald–Hartwig amination). Powerful catalytic activity for the C–N cross-coupling reaction was obtained for the new nanocomposite aerogel, that is, NiO–CuO–CoO/SiO2. The catalyst was characterized by X-ray Powder Diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), elemental mapping and Brunauer–Emmett–Teller (BET). Also, organic compounds were identified by melting point, Fourier-transform infrared spectroscopy (FT-IR) and hydrogen-1 nuclear magnetic resonance (1H NMR) analyses.