Synthesis of Ag nanoparticles as cocatalyst onto CdSe/Al 2 TiO 5 composite photocatalysts for enhancing photocatalytic activity

•The Ag@CdSe/Al2TiO5 showed excellent organic dyes degradation activity.•The surface plasmon resonance effect of Ag promotes the carrier separation.•The metallic Ag can act as the solid-state electron mediator in such system.•Reactive species experiments validate an in-depth photocatalytic mechanism.