Ag₂O/TiO₂ hollow microsphere heterostructures with exposed high-energy {001} crystal facets and high photocatalytic activities

In this paper, one-step hydrothermal method was used to prepare the graded titanium dioxide hollow microspheres, and the {001} crystal plane was exposed. The silver oxide nanoparticles were deposited on the exposed crystal face of titanium dioxide by wet chemical coprecipitation to form Ag₂O/TiO₂ composite material. The samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, nitrogen adsorption–desorption (BET), and so on. The degradation abilities of Ag₂O/TiO₂ composite materials with different molar ratios to rhodamine B were studied under UV–Vis irradiation. And then the mechanism of photocatalytic degradation was analyzed. The experimental results showed that when the molar ratio of titanium dioxide to silver nitrate was 4:1, the degradation effect was best, and the degradation rate reached 95.4% in 80 min. This outstanding photochemical catalysis performance was mainly due to good cooperation, including exposure of specific crystal planes of TiO₂ hollow microspheres and highly scattered Ag₂O nanoparticles, and the p–n heterostructure between Ag₂O and TiO₂ will induce efficient charge separation efficiency.