Ammoxidation of propane to acrylonitrile over silica-supported Fe-Bi nanocatalysts

•Cluster-derived Fe3BiOx/SiO2 is an effective catalyst for propane ammoxidation.•2nm particles are formed on the surface of this material under reaction conditions.•These particles incorporate Fe3+ and Bi3+ components with a 3:1 Fe/Bi atomic ratio.•Co-impregnated Fe-Bi/SiO2 is low active for propane ammoxidation.•Larger particles with surfaces enriched with Fe are formed in this material.