Bimetallic Au3M (M = Ni, Co, Fe) nanoparticles (NPs) were synthesized by reducing a mixture of Au3+ and metal cations (Ni2+, Co2+, Fe3+) by butyllithium in the presence of oleylamine. Au3M NPs were then deposited onto a commercial SiO2 support. The Au3M/SiO2 samples were not particularly active in the catalytic reduction of p-nitrophenol unless they were converted into Au-MO (x) /SiO2 after appropriate thermal treatment in air. The Au-MO (x) /SiO2 catalysts showed good thermal stability and significantly higher p-nitrophenol conversions than Au/SiO2. Relevant characterization was conducted employing X-ray diffraction, transmission electron microscopy, Fourier-transform infrared spectroscopy, and ultraviolet-visible spectroscopy.