A novel fabrication of silver-modified TiO2 colloidal-assembled microstructures and enhanced visible photocatalytic activities

• HCl etching method is a potential technique for the fabrication of the STCMs.
• The photocatalytic activities of the products on removing of Cr(VI) were evaluated.
• The STCMs showed highest photocatalytic activity under visible light irradiation.

Silver-modified TiO2 colloidal-assembled microstructures (STCMs) have been synthesized through a novel and direct hydrothermal hydrochloric acid (HCl) etching combined with soaked Ag-loading process, in which the unique silver-modified 3D spherical hierarchy microstructures were obtained and also amorphous colloidal TiO2 became further crystalline to form unique angular nanoparticles. The physical and chemical properties of STCMs were studied by FESEM, XRD and UV–vis diffuse reflectance spectra (DRS). The photocatalytic activity of the as-prepared STCMs was evaluated by photocatalytic reduction of aqueous solution under visible light irradiation. The experimental results showed that the STCMs exhibited much better photocatalytic activity than that of TCMs and PT (pure TiO2 microspheres) we previously prepared to make a comparison.

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