Construction of Built-in Electric Field within Silver Phosphate Photocatalyst for Enhanced Removal of Recalcitrant Organic Pollutants

摘要

Semiconductor photocatalysis technology has aroused great interest in photocatalytic degradation, but it suffers from the drawbacks of fast electron-hole recombination and unsatisfactory degradation efficiency. Herein, a novel photocatalyst Ag3PO4@NC with excellent photocatalytic activity is successfully prepared, characterized, and evaluated for the efficient removal of organic pollutants. After visible light irradiation for 5, 8, and 12 min, the photocatalytic degradation efficiency of norfloxacin, diclofenac, and phenol on the composite catalyst reaches 100%, and the apparent rate constant of which is 19.2, 48.7, and 23.2 times than that of the pure Ag3PO4, respectively. The density functional theory calculation results indicate that there is a built-in electric field from N-doped carbon (NC) to Ag(3)PO(4)at the interface of the composite catalyst. Driven by the electric field, the photogenerated electrons of Ag(3)PO(4)can be readily transferred to the NC, leading to the efficient separation of photogenerated carriers and the significant improvement of the catalytic performance. The results of radical trapping experiments and electron spin resonance analysis show that photogenerated holes and O(2)(-)play an important role in the photodegradation process. This work provides a universal strategy of construction built-in electric field through coupling with NC to improve the photocatalytic performance of photocatalysts.