Ag/Ag3PO4 nanoparticles assembled on sepiolite nanofibers: Enhanced visible-light-driven photocatalysis and the important role of Ag decoration

Abstract

A novel visible-light-driven Ag/Ag3PO4/sepiolite ternary heterostructure photocatalysts were successfully prepared via a facile precipitation method. The presence of Si–OH on the surface of sepiolite converted the part of Ag + to Ag0 through the in-situ reduction. the visible light degradation rate constant of Rhodamine B by Ag/Ag3PO4/sepiolite was about 3.68 times higher than that of bare Ag3PO4. The superior photocatalytic performance of Ag/Ag3PO4/sepiolite was attributed to the formation of Ag3PO4 particles with smaller grain size and Ag0 nanoparticles due to the introduction of sepiolite, resulting in the enhanced adsorption capacity, improved light response ability and accelerated photogenerated electron transfer rate. In particular, the generated Ag0 played a very important role in improving the electron-hole separation efficiency through acting as the electron acceptor and regulating the carriers’ separation path. On the other hand, the SPR effect of Ag0 can improve the light absorption ability of the photocatalys. The radical trapping experiment showed that holes (h+) and superoxide radical (•O2−) were the main reactive species, where the formation of •O2− was closely related to the presence of Ag0. This work provides new insights for the application of hybrid photocatalysts combined with mineral materials in wastewater treatment.