Synthesis and photocatalytic activity of Ag–Ti–Si ternary modified α-Bi2O3 nanoporous spheres

• Ag–Ti–Si ternary modified α-Bi2O3 nanoporous spheres (TMBS) were prepared.
• Ti modification extends photoabsorptivity of TMBS up to 495 nm.
• Si modification helps to shape the spheres and P103 constructs porous structure.
• Ag modification enhances the separation of photo-generated carriers.
• Singlet oxygen (1O2) and superoxide ion (O2−) are responsible for TCS degradation.

Ag–Ti–Si ternary modified α-Bi2O3 nanoporous spheres (TMBS) were prepared via a solvothermal method, and were characterized by SEM, XRD, N2-sorption and DRS. The particle diameters of TMBS were 500–600 nm and the pore sizes were 20–30 nm. The band gap energy of TMBS was estimated to be 2.51–2.72 eV. TMBS exhibited high photocatalytic activity on the degradation of triclosan (TCS) under UV-light and visible light irradiation (>420 nm). The optimized apparent rate of TCS by TMBS was 0.176 min−1 under UV-light, five times that of TiO2 (P25). By electron spin resonance (ESR) trapping, the photocatalysis mechanism of TCS was ascribed to the photo-generated singlet oxygen (1O2) or superoxide ion (O2−).