The devices, systems and techniques disclosed in this patent document include photocatalytic filter devices and can be used to provide a method for manufacturing a photocatalytic filter with improved adhesion. In addition, the present disclosure of this patent document includes technology to provide a method for reactivating a photocatalytic filter. Using the disclosed techniques, even if a photocatalytic filter is contaminated, the contaminated photocatalytic filter is easily reactivated while maintaining improved adhesion.