Constructing Solid-Gas-Interfacial Fenton Reaction over Alkalinized-C_3N_4 Photocatalyst To Achieve Apparent Quantum Yield of 49% at 420 nm

摘要

Efficient generation of active oxygen-related radicals plays an essential role in boosting advanced oxidation process. To promote photocatalytic oxidation for gaseous pollutant over g- C_3N_4, a solid-gas interfacial Fenton reaction is coupled into alkalinized g-C_3N_4-based photocatalyst to effectively convert photocatalytic generation of H_2O_2 into oxygen-related radicals. This system includes light energy as power, alkalinized g-C_3N_4- based photocatalyst as an in situ and robust H_2O_2 generator, and surface-decorated Fe~(3＋) as a trigger of H_2O_2 conversion, which attains highly efficient and universal activity for photodegradation of volatile organic compounds (VOCs). Taking the photooxidation of isopropanol as model reaction, this system achieves a photoactivity of 2-3 orders of magnitude higher than that of pristine g-C_3N_4, which corresponds to a high apparent quantum yield of 49% at around 420 nm. In-situ electron spin resonance (ESR) spectroscopy and sacrificial-reagent incorporated photocatalytic characterizations indicate that the notable photoactivity promotion could be ascribed to the collaboration between photocarriers (electrons and holes) and Fenton process to produce abundant and reactive oxygen-related radicals. The strategy of coupling solid-gas interfacial Fenton process into semiconductor-based photocatalysis provides a facile and promising solution to the remediation of air poEution via solar energy.