Synthesis of Amino-Functionalized Ti-MOF Derived Yolk-Shell and Hollow Heterostructures for Enhanced Photocatalytic Hydrogen Production under Visible Light

A series of visible-light-active NH2-MIL-125/TiO2/CdS yolk-shell and hollow H-TiO2/CdS hybrid heterostructures were successfully synthesized via the hydrolysis of NH2-MIL-125 metal-organic framework (MOF) using thioacetamide (CH3CSNH2) and cadmium acetate (Cd (CH3COO)(2).2H(2)O) by the post solvothermal method, after which the obtained heterostructures were applied to H-2 photocatalytic production. Among the yolk-shell and hollow heterostructures, NH2-MIL-125/TiO2/CdS (30) and H-TiO2/CdS (30) exhibited the highest H-2 production activity of 2997.482 and 1970. 813 mu mol g(-1)h(-1), with the apparent quantum efficiency of 4.81% and 2.41% at 420 nm, respectively. These superior photocatalytic performances of the heterostructures could be due to the strong interaction of the component based on intimate contact, large surface area, and porous structures that assisted the mass transfer, thereby forming abundant reactive sites. Moreover, the introduction of CdS nanoparticles into the MOF derivatives enhanced the visible light absorption and improved the separation of electron-hole pairs via heterojunction with well-matched energy band gap. Furthermore, the H-2 production rate of the yolk-shell and hollow heterostructures were 18 and 12 times greater than the bare CdS. A probable mechanism was also proposed for the heterostructures. This work could open up new directions for the development of MOF-derived photocatalysts.