Fabrication of novel AgIO4/SnO2 heterojunction for photocatalytic hydrogen production through direct Z-scheme mechanism

Abstract

Direct Z-scheme photocatalysts exhibits many merits as enhanced light harvesting, spatially separated reductive and oxidative active sites, and well-maintained strong redox ability, which improve the performance of various photocatalytic processes. In this research, SnO2 nanoparticles were fabricated by sol-gel route using pluronic as templating agent. However, various proportions of AgIO4 nanoparticles were incorporated on SnO2 surface by sonochemical route. The complete profile of the as-synthesized heterojunctions was assessed by XRD, N2-adsorption-desorption isotherm, DRS, PL, XPS and HRTEM. Among incorporation of AgIO4 nanoparticles, the photocatalytic hydrogen rate soar rapidly indicating that AgIO4 plays a pivotal role in light harvesting and photocatalytic reactivity. The photocatalytic hydrogen production was estimated using methanol as scavenger is 10.7 mmolh−1 g−1 which is 50 fold higher than that of bare SnO2. The pronounced photocatalytic hydrogen rate can ascribed to the production of AgIO4/SnO2 heterojunction through which charge migration was proceeds adopting direct Z-scheme mechanism. The Z-scheme mechanism not only enhances the efficiency of charge carriers separation, but, also, increases the oxidative and reductive power of the photogenerated holes and electrons. The as-synthesized heterojunction retains 85 % its photocatalytic reactivity after five consecutive cycles. XRD and XPS analysis indicates that the heterojunction emerges after cyclic process exhibiting the same crystalline and oxidation state features. The novel photocatalyst enhances the photocatalytic hydrogen production in various industrial applications.