Highly selective fluorescent chemosensor for detecting Hg(II) in water based on pyrene functionalized core-shell structured mesoporous silica

► Pyrene functionalized mesoporous core-shell structured silica was synthesized. ► It is explored as a fluorescent chemosensor for detecting Hg(II). ► A good linear response towards Hg(II) was obtained. ► A detection limit of 3.4×10−9 g mL−1 (down to ppb level) was realized.