The enhanced photocatalytic activity of Ag-Fe2O3-TiO2 performed in Z-scheme route associated with localized surface plasmon resonance effect

A Z-scheme mechanism associated with localized surface plasmon resonance (LSPR) effect is proposed and proved in a ternary Ag-Fe 2 O 3 -TiO 2 composite for photocatalytic reactions. The Ag, Fe 2 O 3 and TiO 2 nanoparticles are prepared to exist in a closely connected Ag-Fe 2 O 3 -TiO 2 heterostructure . Compared to TiO 2 , the addition of Ag-Fe 2 O 3 causes a broad absorption in visible region by LSPR effect of Ag to facilitate electron transfer from TiO 2 to Ag. In addition, electron migration from TiO 2 to Fe 2 O 3 can also be detected, indicating the interface between TiO 2 and Fe 2 O 3 can offer a route with low resistance for charge separation and directional transfer. As a result, photocatalytic activities are greatly improved in Ag-Fe 2 O 3 -TiO 2 , with the highest calculated apparent kinetic constant located at 0.027 min −1 , which is 7.3, 1.9, 1.7 and 1.5 times of Ag-Fe 2 O 3 , TiO 2 , Ag-TiO 2 and Fe 2 O 3 -TiO 2 , respectively. Free radical quenching experiments show that O 2 -∙ and positively charged holes are main oxidative species responsible for the degradation of dyes. Specifically, OH∙ radicals can be hardly found in pure TiO 2 under irradiation but can be extensively produced and participate in the degradation after the addition of Ag-Fe 2 O 3 , which further proves that a Z-scheme route dominates the electron transfer between TiO 2 and Fe 2 O 3 .