Environmentally Sustainable Synthesis of a CoFe2O4–TiO2/rGO Ternary Photocatalyst:A Highly Efficient and Stable Photocatalyst for High Production ofHydrogen (Solar Fuel)

摘要

Herein, a magnetically separable reduced graphene oxide (rGO)-supported CoFe2O4–TiO2 photocatalyst was developed by a simple ultrasound-assisted wet impregnation method for efficient photocatalytic H2 production. Integration of CoFe2O4 with TiO2 induced the formation of Ti³⁺ sites that remarkably reduced the optical band gap of TiO2 to 2.80 eV from 3.20 eV. Moreover, the addition of rGO improved the charge carrier separation by forming Ti–C bonds. Importantly, the CoFe2O4–TiO2/rGO photocatalyst demonstrated significantly enhanced photocatalytic H2 production compared to that from its individual counterparts such as TiO2 and CoFe2O4–TiO2, respectably. A maximum H₂ production rate of 76 559 μmol g^–1 h^–1 was achieved with a 20 wt % CoFe₂O₄- and 1 wt % rGO-loaded TiO₂ photocatalyst, which was approximately 14-fold enhancement when compared with the bare TiO₂. An apparent quantum yield of 12.97% at 400 nm was observed for the CoFe₂O₄–TiO₂/rGO photocatalyst under optimized reaction conditions. This remarkable enhancement can beattributed to synergistically improved charge carrier separation throughTi³⁺ sites and rGO support, viz., Ti–C bonds. Therecyclability of the photocatalyst was ascertained over four consecutivecycles, indicating the stability of the photocatalyst. In addition,it is worth mentioning that the photocatalyst could be easily separatedafter the reaction using a simple magnet. Thus, we believe that thisstudy may open a new way to prepare low-cost, noble-metal-free magneticmaterials with TiO₂ for sustainable photocatalytic H₂ production.