Thermo-responsive functionalized PNIPAM@Ag/Ag3PO4/CN-heterostructure photocatalyst with switchable photocatalytic activity
Linlin Sun, Yaju Zhou, Xin Li, Jinze Li, Dong Shen, Shikang Yin, Huiqin Wang, Pengwei Huo, Yongsheng Yan
Abstract
It is extremely important for photocatalysts to exhibit intelligent responsiveness to their environment. Herein, a poly N -isopropyl acrylamide (PNIPAM)-modified Ag/Ag 3 PO 4 -20/CN hybrid material with excellent convertible photocatalytic activity is prepared. PNIPAM has good hydrophilicity below the lower critical solution temperature (LCST); this increases the capacity of the photocatalyst for adsorbing tetracycline (TC) molecules. In addition, the PNIPAM-modified Ag/Ag 3 PO 4 -20/CN can prevent the loss of Ag 3 PO 4 . The dispersity is improved by loading g-C 3 N 4 nanosheets (CN) for enhancing the efficiency of photocatalytic activity. Furthermore, a Z-scheme heterostructure is formed between CN and Ag 3 PO 4 , accelerating the separation efficiency of the holes and electrons. Ag nanoparticles can be used as electron-shuttle mediators, and electrons receiving more energy are transferred via the localized surface plasmon resonance (LSPR) effect. Furthermore, the PNIPAM@Ag/Ag 3 PO 4 -20/CN photocatalyst exhibits an excellent degradation rate for the degradation of TC when the temperature is lower than the LCST. The photoluminescence spectra and photocurrent curves prove that the carrier-separation efficiency of PNIPAM@Ag/Ag 3 PO 4 -20/CN is higher than those of Ag/Ag 3 PO 4 /CN and CN. The main active species of ·O 2 − and h + are detected to reveal the plausible mechanism of the PNIPAM@Ag/Ag 3 PO 4 -20/CN hybrid material system. This work provides a way to develop intelligent materials for switchable photocatalytic applications.