Construction of novel direct Z-scheme AgIO4-g-C3N4 heterojunction for photocatalytic hydrogen production and photodegradation of fluorescein dye

Highly mesoporous AgIO4/g-C3N4 heterojunctions were synthesized by sonochemical route for exceptional photocatalytic degradation of fluorescein dye (FLU) and hydrogen production. AgIO4 nanoparticles are deposited on the corners and edges of the wrinkled sheets of g-C3N4. Mass ratio of AgIO4 acted a pivotal part in enhancing the photocatalytic reactivity. Due to the small difference between the valence band potential of g-C3N4 (EVB = +1.4 eV) and conduction band potential of AgIO4 (ECB = +1.08 eV), a perfect direct Z-scheme mechanism is constructed. Noticeably, the removal of fluorescein dye reach 98% and the rate of hydrogen produced is 23 mmolh−1 g−1. Taking the benefits of matching the band energy structure, AgIO4/g-C3N4 heterojunction enhances the recombination of the useless positive hole and electron in the inferior valence and conduction band of g-C3N4 and AgIO4, respectively through Z-scheme aspects. However, the holes and electrons in the higher valence and conduction band are preserved with strong oxidation and reduction power. This Z-scheme mechanism not only enhances the quantum efficiency of charge separation, but also, increase the oxidative and reductive power of the charge carrier. Positive holes and the superoxide radicals are the main reactive species confirmed the Z-scheme mechanism. This research work give a hot spot in synthesis of low cost novel photocatalyst for hydrogen production and wastewater treatment.