An In Situ Simultaneous Reduction‐Hydrolysis Technique for Fabrication of TiO2‐Graphene 2D Sandwich‐Like Hybrid Nanosheets: Graphene‐Promoted Selectivity of Photocatalytic‐Driven Hydrogenation and Coupling of CO2 into Methane and Ethane

Abstract

A novel, in situ simultaneous reduction‐hydrolysis technique (SRH) is developed for fabrication of TiO 2‐‐graphene hybrid nanosheets in a binary ethylenediamine (En)/H 2 O solvent. The SRH technique is based on the mechanism of the simultaneous reduction of graphene oxide (GO) into graphene by En and the formation of TiO 2 nanoparticles through hydrolysis of titanium (IV) (ammonium lactato) dihydroxybis, subsequently in situ loading onto graphene through chemical bonds (Ti–O–C bond) to form 2D sandwich‐like nanostructure. The dispersion of TiO 2 hinders the collapse and restacking of exfoliated sheets of graphene during reduction process. In contrast with prevenient G‐TiO 2 nanocomposites, abundant Ti 3+ is detected on the surface of TiO 2 of the present hybrid, caused by reducing agent En. The Ti 3+ sites on the surface can serve as sites for trapping photogenerated electrons to prevent recombination of electron–hole pairs. The high photocatalytic activity of G‐TiO 2 hybrid is confirmed by photocatalytic conversion of CO 2 to valuable hydrocarbons (CH 4 and C 2 H 6) in the presence of water vapor. The synergistic effect of the surface‐Ti 3+ sites and graphene favors the generation of C 2 H 6, and the yield of the C 2 H 6 increases with the content of incorporated graphene. The work may open a new doorway for new significant application of graphene for selectively catalytic C–C coupling reaction