Synthesis and photocatalytic activity of Cu2O hollow nanospheres/TiO2 nanosheets by an in-situ water-bath method

In this work, a simple in situ water-bath method is used to load Cu2O hollow nanospheres (named as H-Cu2O) on TiO2 nanosheets (named as TiO2-NS). H-Cu2O of 160-250 nm in diameter is uniformly supported on the surface of TiO2-NS. H-Cu2O has a novel hollow core-shell structure with a double shell. Specifically, the diameters of inner hollow spheres are 80-90 nm and the thickness of the outer shell and inner shell are about 40 nm and 25 nm, respectively. It is conjectured that the outer and inner shells of H-Cu2O can both provide adsorption and reaction sites, favoring the photocatalytic reaction. The UV-visible diffused reflectance spectra show that compared with TiO2-NS the H-Cu2O/TiO2-2 sample with adding 80 mg of TiO2-NS shows a stronger visible light absorption. Furthermore, the steady-state photoluminescence (PL) and photocurrent spectra show that H-Cu2O/TiO2-2 has a weaker PL intensity at about 370 nm and 6 times higher photocurrent intensity than TiO2-NS, demonstrating that H-Cu2O/TiO2-2 has higher charge separation efficiency. Compared with TiO2-NS, the photocatalytic activity of H-Cu2O/TiO2-2 under UV light (lambda <= 400 nm) increase by 6.3 times for the degradation of methyl orange. The improved photocatalytic activity can be attributed to the enlarged BET areas (6.1 m(2) g(-1)/H-Cu2O/TiO2-2 vs. 3.8 m(2) g(-1) /TiO2-NS), the enhanced light adsorption, and the improved charge separation efficiency. The reported in situ water-bath method is simple, mild, and general, which could be extended to other novel composite materials. (C) 2021 Elsevier B.V. All rights reserved.