Preparation Of Hierarchical Porous RGO/TiO₂ Composites With Different Templates And Its Photocatalytic Properties

The environmental pollution caused due to the widespread application of tetracycline antibiotics has threatened the stability of the entire ecosystem.The photocatalysis technology has become a hot spot of research for the degradation of antibiotic pollution,because of its high efficiency,environmental protection,low cost,etc.In this study,a series of hierarchical porous rGO/TiO₂?PS?and rGO/TiO₂?yeast?composites were synthesized by sol-gel method combined with ultraviolet irradiation reduction using polystyrene spheres?PS?and yeast as macroporous templates,respectively,and citric acid as hydrolysis inhibitor and mesoporous template.The materials were characterized and analysed by X-ray diffraction?XRD?,scanning electron microscope?SEM?,Raman spectroscopy,Brunauer-Emmett-Teller?BET?,UV-visible diffuse reflectance spectroscope?UV-vis DRS?,photoluminescence?PL?spectroscopy technology.The influence of different mass fractions of PS and yeast on the adsorption,photocatalytic properties and reaction rate of hierarchical porous rGO/TiO₂ composites by using tetracycline hydrochloride?TTCH?as the target degradant were studied.rGO/TiO₂?5wt%PS?and rGO/TiO₂?20wt%yeast?were used as samples to evaluate the cyclic stability of composites.And monodisperse rGO/TiO₂?yeast?hollow microspheres were prepared adopting yeast template on the experimental method of hierarchical porous rGO/TiO₂?yeast?.The conclusions have obtained from the experiments:1.The TiO₂ in hierarchical porous rGO/TiO₂ possesses high degree of crystallization.The introduction of PS could not change the crystal structure of TiO₂,and the introduction of yeast could inhibit the transformation of anatase phase into rutile phase.the low amount of carbon left after heat treatment due to debinding of PS and yeast could dope with TiO₂ to extended the photogenic carrier life of TiO₂ and broaden its optical response range to enhance photocatalytic activity together with rGO.2.The addition of macroporous template PS and yeast could increase the specific surface area,adsorption property and photocatalytic activity of hierarchical porous rGO/TiO₂ composites,and the bio-template yeast has a better promotion effect on the above properties of the composite materials.3.Hierarchical porous rGO/TiO₂ composites showed high photocatalytic activity under visible light and ultraviolet light.The highest photocatalytic activity were present by rGO/TiO₂?5wt%PS?and rGO/TiO₂?20wt%yeast?composites,the degradation rate reached 87.67%and 90.03%under visible light,respectively,and photodegradation rate reached 94.78%and 91.65%under the ultraviolet light,respectively.And the composites all exhibt excellent cyclic stability.4.Monodisperse rGO/TiO₂?yeast?hollow microspheres copied the morphology and size of original yeast cells well and the TiO₂ was amorphous phase.The optimal adsorption efficiency of hollow microspheres materials was 73.31%,which was 26.99%above hierarchical porous rGO/TiO₂?20wt%yeast?.