Facile preparation of Au/Ag bimetallic hollow nanospheres and its application in surface-enhanced Raman scattering

► Hollow Au/Ag bimetallic nanospheres were synthesized using a modified SiO2 nanoparticle-templating method. ► The as-prepared hollow Au/Ag nanospheres structured films are used for the first time as SERS substrates. ► They exhibit good SERS enhancement ability, excellent reproducibility, and stability, which may find practical application for routine SERS analysis. ► The Au/Ag bimetallic hollow nanostructured aggregate, interconnected nanostructured aggregate and nanoscale roughness are important factors for SERS enhancement ability.