A Facile Cooling Strategy For The Preparation Of Silica Nanoparticles With Rough Surface Utilizing A Modified Stober System

The well-known St ober method has been widely used to synthesize dense silica particles with smooth surface, however, the preparation of silica nanoparticles with rough surface (RS-SiO2 NPs) based on Stober system via a facile one-pot method has not been achieved. Herein, a modified Stober system (i.e., a specific ternary tetraethyloxysilane (TEOS)/ethanol (EtOH)-water (H2O) with a precise molar ratio of 1: 45.8: 124) is used to prepare the primary SiO2 NPs with low-condensed silica shell (LCSS) and unreacted TEOS. Subsequently, via a simple one-step cooling treatment, the RS-SiO2 NPs with spherical morphology (177 nm), large specific surface area (85 m(2) g(-1)) and controllable density were successfully prepared. Various experimental conditions, such as prereaction time (reaction time of primary SiO2 NPs at room temperature before cooling treatment), cooling temperature (cooling treatment temperature) and ammonia solution concentration were studied. The results show that the migration rate of the unreacted TEOS in the primary SiO2 NPs plays an important role in the formation of RS-SiO2 NPs. This paper also provides us with a new idea to further understand the formation mechanism of SiO2 particles by the Stober method. The RS-SiO2 NPs loaded with gold nanoparticles can effectively reduce 4-nitrophenol to 4-aminophenol.