Synthesis and characterization of cube-like Ag@AgCl-doped TiO2/fly ash cenospheres with enhanced visible-light photocatalytic activity

• The cube-like Ag@AgCl and the film of TiO2 are deposited on the surface of FAC.
• The narrower band gap energy of catalyst is ascribed to the synergistic effect between Ag N-Ps and TiO2.
• OH trapping PL spectra of the Ag@AgCl–TiO2/FAC composite was discussed.
• The mechanism of photocatalytic degradation with Ag@AgCl–TiO2/FAC was investigated.

A cube-like Ag@AgCl-doped TiO2/fly ash cenosphere composite (denoted Ag@AgCl–TiO2/fly ash cenospheres) was successfully synthesized via a two-step approach. The as-prepared catalysts were characterized by scanning electron microscopy, X-ray diffraction, diffuse reflectance ultraviolet–visible spectroscopy, Brunauer–Emmett–Teller, and X-ray photoelectron spectroscopy. The photocatalytic experiment showed that the rhodamine B degradation rate with Ag@AgCl–TiO2/fly ash cenospheres was 1.56 and 1.33 times higher than that with AgCl–TiO2/fly ash cenospheres and Ag@AgCl, respectively. The degradation ratio of rhodamine B with Ag@AgCl–TiO2/fly ash cenospheres was nearly 100% within 120 min under visible light. Analysis of active species indicated that O2− and h+ dominated the reaction, and OH participated in the photocatalytic reactions as an active species. A mechanism for the photocatalytic degradation by the Ag@AgCl–TiO2/fly-ash cenospheres was also proposed based on the experimental results.

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