Silica nanosphere–graphene oxide (SiO2–GO) hybrid catalyzed facile synthesis of functionalized quinoxaline derivatives

Herein, fabrication of spherical SiO2 nanoparticles (5 ± 0.2 nm) with uniform size is followed by their homogeneous distribution on graphene oxide (SiO2–GO) by using a simple in situ one-step method. These as synthesized catalytic materials are further characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and others. This spectroscopic characterization demonstrated that GO acted as a good supportive substrate for controlling the size and activity of SiO2 nanospheres with their cooperation towards catalytic reactions. The optimized hybrid exhibited high catalytic activity for the synthesis of functionalized quinoxalines. Significantly, the as-synthesised SiO2–GO nanohybrid catalysed reaction, for the first time, was shown to be highly efficient in mild conditions (i.e., room temperature, air) with excellent product yield (92 %) and good recyclability (up to four cycles) at room temperature.