The Research On Synthesis And Properties Of Sea-urchin Like Ag/RGO/TiO₂ Micro/Nano Composite

Nano-TiO₂ semiconductor has attracted much attention on the area of photocatalytic degradation for organic pollutant,lithium ion battery,photocatalytic Hydrogen Production,Dye-Sensitized Solar Cell and Perovskite solar cell because of its non-toxicity,environmental friendliness,high chemical stability,high thermal stability and low price.However,its disadvantages also immensely limit its application.For example,TiO₂ could adsorb ultraviolet light that is only 5% of solar energy due to its large band gap of 3.2 eV,leading to the low utilization of TiO₂ for solar light;in addition,the high recombination rate decreases the number of effective photo-generated electrons and holes,which leads to the low quantum efficiency.Thus,it is necessary to modify TiO₂ for enhancing its property.In the past,the ways had been reported to modify Ti O₂ for enhancing property effectively includes crystal control,morphology control,ion-doping,semiconductor compounding,dye sensitized and noble metal load.In this paper,morphology control,material compounding and noble metal load were used together to modify TiO₂ for extending the visible light absorption and hindering the recombination of photo-generated electron-hole pairs.Three dimension?3D?urchin-like TiO₂/reduced graphene oxide?RGO?/Ag?UTG-Ag?mocro/nano composite was synthesized via two steps method,including solvothermal and hydrothermal method,in which tetrabutyl titanate?TBT?and titanium tetrachloride were used as titanium source and graphene oxide?GO?and silver nitrate were used as reagent.Accordingly,3D urchin-like TiO₂/reduced graphene oxide?UTG?mocro/nano composite were also synthesized in the same condition.The influence of hydrothermal reaction temperature,reaction time on the morphology of UTG composite were investigated by SEM analysis.The morphology,crystal structure,compositions,optical and photocatalystic performance were analysized in this text.The results are as follows:?1?3D urchin-like TiO₂?UT?assembled with one dimensional nanoroads were synthesized through solvothermal reaction with TBT and titanium tetrachloride as titanium source;UTG composite containing different concentration of reduced graphene oxide?0 wt.%,2.5 wt.%,5 wt.%,7.5 wt.%,10 wt.%?were synthesized through hydrothermal reaction with UT and GO as raw materials.SEM analysis demonstrate that excessive reaction temperature and reaction time could destroy the urchin-like morphology of UTG composite,and indicate that UTG composite synthesized under the conditions of hydrothermal reaction at 150 ?and 6 hours possess good morphology of urchin-like.XRD and TEM analysis indicate that TiO₂ contained in UTG composite consist of rutile phase;FT-IR,Raman spectroscopy and XPS analysis indicative of the successful reduction of GO to RGO;FT-IR spectroscopy and XPS analysis confirmed the formation of Ti-O-C bond between UT and RGO,which is favor of combining of UT and RGO.UV–visible spectrum showed that UTG composite obviously redshift to about 430 nm and has strong absorption in visible light;the photocatalytic degradation experiment of UTG composite for RhB showed enhanced photocatalytic ability compared with UT and P25 due to the combination of RGO,in which UTG-5% exhibited the highest photodegradation of RhB after 3 h magnetic stirring in dark and 3 h irradiation with Xenon lamp,reaching to 98.7%.?2?UTG-Ag composite containing different mole ratio of Ag?Ag/Ti was designed as 0%,3%,5%,7%,9%?were synthesized through hydrothermal method with UT,GO and AgNO3 as raw materials,in which all the composites contain same amount of RGO which is 5 wt.% of UT.SEM and TEM analysis indicated that UTG-Ag composite synthesized under the conditions of hydrothermal reaction at 150 ?and 6 hours possess good morphology of urchin-like.XRD and TEM analysis indicated that TiO₂ contained in UTG-Ag composite consist of rutile phase;FT-IR,Raman spectroscopy and XPS analysis indicative of the successful reduction of GO to RGO;FT-IR spectroscopy and XPS analysis confirmed the formation of Ti-O-C bond between UT and RGO,which is favor of combining of UT and RGO.Nano Ag particles loaded on the surface of nanoroads assembled into urchin-like UTG-Ag microsphere could be seen clearly in TEM image.XPS and EDS spectroscopy confirm the existence of Ag.UV–visible spectrum illustrated that UTG-Ag composite has better optical performance than UTG composite;what's more,UTG-Ag composite showed broad peak in visible light region due to noble metal nano Ag exhibited surface Plasmon resonance?LSPR?phenomenon.The photocatalytic degradation experiment of UTG-Ag and UTG composite for RhB demonstrated that UTG-Ag composite has better photodegradation ability than UTG composite,in which UTG-Ag composite degraded 98.45% of RhB after 3 h magnetic stirring in dark and 90 mins irradiation with Xenon lamp.