Structural characteristics of a Ni–Ag magnetic catalyst and its properties in soybean oil hydrogenation

•A Ni–Ag magnetic catalyst was assessed for soybean oil hydrogenation.•Prepared catalysts were characterized by ICP-OES, XRD, TEM and N2 isotherms.•Ni dispersion on PVP-DB-171/SiO2/Fe3O4 NPs was improved by incorporating Ag promoter.•Ni–Ag0.15/PVP-DB-171/SiO2/Fe3O4 catalyst had the highest catalytic activity.•TFAs in hydrogenated soybean oil was decreased to 10.4% after 90min.