Cerium-doped gehlenite supporting silver/silver chloride for continuous photocatalysis

Abstract

Herein a series of cerium-doped gehlenite supporting silver/silver chloride (Ca₂Al₂SiO₇:Ce³⁺–Ag/AgCl) composites are successfully fabricated and their phase structure, surface property, morphology and optical properties are examined. The Ca₂Al₂SiO₇:Ce³⁺ shows a strong emission at 410 nm and a long-lasting afterglow is observed additionally. The emission and afterglow intensities are weakened by the decoration of Ag/AgCl particles, which is caused by photoemission quenching and, partially, the internal filtering effect due to the decorated species. Such Ca₂Al₂SiO₇:Ce³⁺–Ag/AgCl composites can efficiently degrade methyl orange under solar irradiation, and this degradation proceeds continuously after the elimination of the external irradiation because of the long-lasting luminescence of the phosphor. Around 15% of methyl orange can be degraded after light-off. Moreover, it was found that Ag/AgCl is more suitable to compose with Ca₂Al₂SiO₇:Ce³⁺ as compared to TiO₂ because of its wide absorption window.