MOF assisted synthesis of TiO2/Au/Fe2O3 hybrids with enhanced photocatalytic hydrogen production and simultaneous removal of toxic phenolic compounds

Abstract

The heterojunction photocatalyst namely TiO2/Fe2O3 modified with different Au loadings has been constructed via a one-pot metal-organic framework (MOF) route which using titanium (IV) butoxide and iron nitrate as precursors. The characteristics studies show that the nano-shaped TiO2 is spreaded uniformly on the surface of Fe2O3 along with Au deposition. The noble Au metal acts as an electron mediator which has been enabled in enhancing the photocatalytic performances of TiO2/Fe2O3 heterojunction. The photocatalytic ability was evaluated through the H2 production (using water-splitting reaction) and removal of phenolic compounds namely 2,4 dichlorophenol (2,4-DCP) and 4-bromophenol (4,B,-P) under the largely available visible light in solar spectrum. The highest H2 production of 590 μmol g−1 h−1, with an apparent quantum yield of 12%, was obtained using the glycerol as sacrificial reagent using 4% Au-Fe2O3/TiO2 photocatalyst. By examining the special impact of different scavengers, it paraded that the hydroxyl and superoxide radicals mainly participated in the photocatalysis process. The combined effect of TiO2 and Fe2O3 and effective Au deposition lead to an upgraded carrier separation efficiency and outstanding photocatalytic performances. Furthermore, the close interface formed by metallic Au material pointedly slows down the recombination of e−/h+, which is high advantageous for the photocatalytic processes using naturally available sunlight or visible-light. This work delivers a novel perception to develop a stable noble-metal photocatalyst material in the H2 production and the removal of phenolic compounds in the industrial areas.