MIL-53 (fe) for Constructing Hydrogenated Fe3O4@C@TiO2 Double Core-Shell Nanocrystals As Superior Bifunctional Photocatalyst

Heterogeneous photocatalysis is a promising technology to overcome the problems associated with the energy crisis and environmental pollution. Therefore, the design of a reusable dual function photocatalyst has been studied extensively. Herein, MIL-53 (Fe) was used to fabricate Fe3O4@C on which TiO2 was deposited via a solgel route to form Fe3O4@C@TiO2 (FCT) double core-shell nanocomposite. Thermal treatment effect on photocatalytic activity under different atmospheres (air, argon and hydrogen) has been investigated. Then, the temperature was optimized (300-400 degrees C) under hydrogen atmosphere. Furthermore, the photocatalytic performance of the prepared composite on Rose Bengal (RB) dye degradation and hydrogen generation via water-splitting has been evaluated. The FCT sample treated at 350 degrees C in H2-atmosphere (FCT/H350) showed significant improvement in photodecomposition of 100 ppm of RB which completely disappeared within 40 min of the reaction. The apparent rate constant of FCT/H350 was 8.71 x 10-2 min-1, which is 4-folds faster than that of bare-TiO2. Moreover, the FCT/H350 exhibited an initial hydrogen generation rate (HGR) of 1593 mu mol.g- 1.h- 1. Spectroscopic and electrochemical measurements were conducted to investigate the possible photocatalytic mechanism and photogenerated charge carriers pathway. This study aims to develop a magnetically separable, highperformance, and bifunctional catalyst for photocatalytic applications.