Synthesis and Characterization of Bi3+-Doped Ag/AgCl and Enhanced Photocatalytic Properties

Bi 3+ -doped Ag/AgCl photocatalytic materials were synthesized using a simple coprecipitation approach. Powder X-ray diffraction analysis revealed that Bi 3+ was inserted into the crystal lattice of AgCl to partially replace Ag +, resulting in the contraction of AgCl lattice. Ultraviolet–visible absorption tests showed that the dopant Bi 3+ slightly widened the band gap of AgCl as it raised the conduction level. X-ray photoelectron spectroscopy revealed the strong interaction between Bi 3+, Ag +, and Cl –, and also showed the presence of abundant Bi 3+ on the surface of AgCl particles. Methyl orange (MO) photodegradation experiment showed the photocatalytic activity of the Bi 3+ -doped Ag/AgCl was significantly dependent on the amount of doped Bi 3+ . The Bi 3+ -doped Ag/AgCl (2 wt %) reached the highest activity of 91% after 8 min, while the pure Ag/AgCl degraded only 32% of MO. The degradation rate constant of Bi 3+ -doped Ag/AgCl was 3.75 times higher than that of pure Ag/AgCl. Electron spin resonance showed that • OH was the main active species during the oxidation of MO using the Bi 3+ -doped Ag/AgCl. During the photodegradation of MO, the photocatalytic activity of Ag/AgCl was first enhanced and then weakened along with the increased amount of Bi 3+ . These changes were theoretically attributed to the formation of chloride dangling bonds and vacancies induced by the dopant Bi 3+ . The chloride dangling bonds from Bi 3+ also enhanced the photocatalytic activity of Ag/AgCl.