Rhodamine B immobilized on hollow Au-HMS material for naked-eye detection of Hg2+ in aqueous media

► Au-HMS-Probe is prepared via AuN bonds. ► Gold nanoparticles are chosen as connectors instead of silane agents. ► Au-HMS is chosen as carrier for the first time. ► The immobilization method of Au-HMS-Probe is very simple and effective. ► Au-HMS-Probe shows excellent ability for detecting Hg2+ by naked-eye.