Enhanced photocatalytic degradation of RhB dye from aqueous solution by biogenic catalyst Ag@ZnO

•Ecofriendly synthesis of Ag decorated ZnO nanoparticles was carried out.•Carya illinoinensis leaves extract was used as reducing and capping agent.•Decoration of Ag increased the photocatalytic activity due to trapping of electrons.•The effect of various factors were examined, degradation kinetic of dye (Rhodamine B) obeyed pseudo first order model.