Fig. 6: Photocatalytic H2O2 synthesis in reactor systems under simulated and natural sunlight.

a Development history of photocatalytic synthesis of H2O2 for industrial applications in reactors, b Comparison between simulated sunlight and natural sunlight, c Laboratory-scale flow-reactor system for H2O2 photocatalysis under simulated sunlight, d Flow-method H2O2 production and solar-to-chemical (SCC) efficiency under simulated sunlight, e Open-air flow-reactor system for H2O2 photocatalysis under natural sunlight, f Flow-method H2O2 production and SCC efficiency under natural sunlight irradiation.