Preparation and visible-light photocatalytic property of a novel ternary dual Z-scheme g-C3N4/Ag6Si2O7/AgBr heterojunction

In recent years, ternary heterojunction catalysts have emerged owing to their exceptional properties for integrating the advantages of various materials, enabling the efficient separation of photoinduced charges and enhanced redox performance. In this study, a novel dual Z -scheme g-C 3 N 4 /Ag 6 Si 2 O 7 /AgBr (CNASAB) photocatalyst was prepared using a one-step coprecipitation method. Its catalytic performance was assessed through the photodegradation of tetracycline hydrochloride (TC) and Rhodamine B (RhB). The results showed that among various CNASAB compositions, CNASAB6 exhibited the highest catalytic activity. The catalyst achieved complete degradation of RhB within 6 min under visible light irradiation, with catalytic rates 73.7, 53.0, and 6.8 times higher than those of the individual components, g-C 3 N 4 , Ag 6 Si 2 O 7 , and AgBr, respectively. Additionally, the catalyst exhibited significant degradation of TC with an efficiency of 63.38 % within 2 min, indicating a broadened degradation ability. Ultraviolet-visible diffuse reflectance spectroscopy, photoluminescence spectroscopy and electrochemical impedance spectroscopy analyses confirmed that the ternary heterojunction broadened the spectral response range, reduced electrochemical impedance, and improved the separation of photoinduced electron-hole pairs. The successful construction of this ternary heterojunction not only provides a promising strategy for the photocatalytic degradation of organic pollutants but also has substantial potential for environmental purification applications.