Highly selective epoxidation of styrene over gold–silica catalysts via one-pot synthesis: synthesis, characterization, and catalytic application

A series of Au–silica (nanosphere) catalysts were prepared by in situ synthesis; highly dispersed gold nanoparticles (GNPs, 6.4 nm) were obtained, and catalytic tests showed good catalytic activity and epoxidation selectivity. To investigate the origin of the GNPs, the solids were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and other instruments. Some reaction parameters, such as solvent, oxidant concentration, catalyst concentration and reaction time, have been investigated and reaction conditions are optimized.