Highly fluorescent silicon quantum dots decorated silica microspheres for selective detection and removal of Au3+ and subsequent catalytic application

[Display omitted] •Silicon quantum dots were prepared and decorated on silica, giving SiO2-SiQDs.•The detection and adsorption of Au3+ were achieved synchronously with SiO2-SiQDs.•Adsorbed Au3+ was in situ transformed to gold nanoparticle with high catalytic ability. Sensitive detection and efficient removal of Au3+ are important for environmental monitoring and remediation. In this study, silicon quantum dots (SiQDs) were prepared with 3-aminopropyl trimethoxysilane as the silicon source and boric acid as the doping substance to enhance fluorescence quantum yield. The obtained SiQDs possessed fluorescence sensing ability of Au3+ and were successfully decorated on the mesoporous silica microspheres (SiO2), giving SiO2-SiQDs. Owing to the high affinity for Au3+ and the relatively large surface area, the SiO2-SiQDs exhibited not only selective fluorescence detection of Au3+ in water matrix with a relatively low limit of detection (13.67μgL−1), but also efficient adsorption of Au3+ with a maximal adsorption capacity of 530.7mgg−1. Besides, the Au3+ adsorbed on the SiO2-SiQDs could be in-situ reduced into evenly dispersed small-size gold nanoparticles, showing high catalytic efficiency for the reduction of 4-nitrophenol. The remarkable performance of SiO2-SiQDs on detection, adsorption and reusability demonstrated its multi-purposed applicabilities.