Ultrahigh-performance visible-light photodegradation enabled by direct Z-scheme AgI/(Na,F)–C3N4 composites

Abstract Preparation of high-performance semiconductor photocatalysts is often considered to be the challenge and focus in dealing with water contaminations, and attracts numerous concerns and research interests nowadays. In this work, high-performance Z-scheme AgI/(Na,F) doped g-C3N4 composites were synthesized by facile calcination and in-situ deposition methods and employed for ultrahigh-performance degradation of broad-spectrum antibiotics contaminants. The prepared (Na,F) doped g-C3N4 showed narrower bandgaps, enhanced solar-light absorption, and highly improved visible-light photocatalytic performance. Besides, the strong combined interfaces between AgI nanoparticles and (Na,F) doped g-C3N4 was contributing to visible-light harvesting and highly boosted charge separation of the samples, among which AgI/(Na,F)–CN-40% composite presented the best visible-light photocatalytic performance. The photocatalytic reaction rate constant of the AgI/(Na,F)–CN-40% composite was as high as approximately 0.2007 min−1, which was 65.80 times of pristine g-C3N4 and 3.60 times of AgI, mainly because of the construction of direct Z-scheme charge transfer pathways between AgI and (Na,F) doped g-C3N4. Finally, the radical scavenger experiments, possible degradation pathways, and photocatalytic mechanism were also proposed.