Construction of a novel Ag2O/P-g-C3N4 p-n type heterojunction for efficient degradation of organic pollutants under visible light irradiation

Abstract

It is critical to design efficiently stable photocatalysts for removing organic waste from water. Herein, a sequence of Ag2O/Phosphors-doped g-C3N4 (AgO/PCN) composites with p-n heterojunctions were successfully prepared via facile chemical deposition for photocatalytic degradation of Rhodamine 6G (Rh 6G) and Levofloxacin (LVFX). The resultant composites with an optimal AgO/PCN ratio of 2:1 could degrade approximately 99 % of Rh 6G and 83 % of LVFX in 50 and 120 min, respectively, under visible light irradiation, which is obviously more than pure Ag2O and Phosphors-doped g-C3N4. The increased performance of photocatalysis could be because of the broadened light absorption range originated from Ag0 surface plasmon resonance effect (SPR) and the accelerated separation efficiency of electron-hole pair via p-n junction. Radical trapping and Electron Paramagnetic Resonance experiments confirmed that [rad]O2− and h+ were the chief active species, and [rad]OH was the minor active species for Rh 6G degradation process. Therefore, a plausible mechanism theorized on the basis that the synergistic effect of surface plasmon resonance and p-n heterojunction for increased photocatalytic activity is proposed. This work advances a novel idea for establishing highly efficient catalysts via synergizing surface plasmon resonance and p-n heterojunction, paving the way for efficient photocatalytic removal of organic pollutants in water.