Preparation And Application Of CDs@TiO₂ Hollow Microspheres

Titanium oxide?TiO₂?,a n-type semiconductor with the band gap of about 3.2 eV at room temperature,becomes one of the most promising candidates for solving global problems of alternative energy and environment due to it's optical properties,chemical stability,environment friendly and high photocatalytic.However,the surface modification of TiO₂ plays the most important part in influencing the photocatalytic performance since the photocatalytic reaction usually occurs on the surface of the TiO₂.In this work,we combined the templating-free methods for fabricating TiO₂ hollow microspheres?THM?and the one-pot methods for fabricating carbon dots?CDs?.Thus,we developed a novel one-pot fabrication of THM doped with CDs by hydrothermal treatment of acidic TiCl4 solution with NH4F and citric acid for the first time.The main work of the article was as follow:1.One-pot method has been developed to synthesize THM,in which TiCl4 and NH4F were used as raw material.The diameter of the as-prepared THM is about 1.5 ?m in size with the hollow pore size at around of 200 nm.The result shows that the optimum reaction conditions is:molar ratio of NH4F:TiCl4 is 4:1,reaction temperature is 180 ?,reaction time is 9 h.2.Explored the up-convertion properties of different CDs which all fabricated via one-step hydrothermal way.The result shows that among those kinds of CDs the CDs made by citric acid and ethylene diamine exhibit the best up-convertion properties.A new convenient method has been developed to synthesize CDs@THM,in which titanium tetrachloride,ammonium fluoride,citric acid and ethylene diamine were used as raw material.The diameter of the as-prepared is around 1.5 ?m with the hollow pore size at around of 200 nm.The production 's band gap is 2.36 eV exhibit excellent visible-light photocatalytic activity for the degradation of organic pollutants.The the optimum reaction conditions is:reaction temperature is 180 ?,reaction time is 9 h.