Synthesis,Characterization And Applications Of Ti-contained Carbon Nitride Composites

In order to improve the fluorescence quantum yield?Q.Y.?and expand the application scope of functional carbon nitride,Ti-contained functional carbon nitride nanoflakes?Ti-CNNFs?and Ti-contained functional carbon nitride polymers?Ti-CNNPs?were synthesized and used to detect HClO or riboflavin in real water samples or tablets.Besides,a simple and quick way was set up for synthesizing titanium dioxide/graphitic carbon nitride?TiO₂/g-C₃N₄?composites.The ability of the prepared TiO₂/g-C₃N₄ composites in degrading methylene blue?MB?under visual light was tested.The main research contents are as follows:?1?The Ti-CNNFs with a Q.Y.of 13.7%were synthesized from butyl titanate,citric acid monohydrate and urea by the facile one-step oil-thermal method.Various characteristic techniques such as TEM,AFM,XRD,IR and XPS were performed to demonstrate its nanoflake-like in shape,functionalized and graphitic carbon nitride structure.The prepared Ti-CNNFs displayed good selectivity,stability and strong anti-interference performance in detecting HClO with a relatively low limit of detection?0.20?M?and a broad linear range?0.20-70?M?.The fluorescence mechanism may be derived from the n?^*transition of the p–?conjugation of C=O,C=N,O-H and N-H.The fluorescence quenching mechanism of detecting HClO is thought to be that HClO oxidizes and destroys the big conjugation structure of Ti-CNNFs.?2?The Ti-FCNPs with an optimal Q.Y.of 35.6%were synthesized from butyl titanate,L-tartaric acid and urea by the facile one-step oil-thermal strategy.Various characterization techniques such as TEM,XRD,IR and XPS were performed to demonstrate its polymer-like in shape,functionalized and graphitic carbon nitride structure.It is thought that Ti doped into Ti-FCNPs by the way of forming the metal complexs.The prepared Ti-FCNPs showed excellent selectivity in detecting riboflavin with a limit of detection of 0.12?g/mL and a corresponding linear range of 0.12⁷.5?g/mL.The method also possesses satisfactory anti-interference capability.The detection mechanism was ascribed to the fluorescence resonance energy transfer?FRET?,Ti-FCNPs were as donor and riboflavin was as receptor.?3?The TiO₂/g-C₃N₄ composites were synthesized from butyl titanate,citric acid monohydrate and urea by a simple and quick two-steps strategy.Compared to traditional ways of synthesizing TiO₂/g-C₃N₄ composite,the two-steps strategy grately decreased the reaction time from dozens of hours to be within 10 hours.Various characterization techniques such as TEM,XRD and XPS were performed to testify the prepared materials.Excitingly,MB can be catalyzed and degraded by the prepared TiO₂/g-C₃N₄ under 420⁸00 nm visual light in a rate of 0.0490 min^-1,which is 24.5 times of MB self-degredation.The mechanism of catalysis and degradation in this research is considered to be that the h⁺and the·O₂^–oxidize and destroy the conjugated structure of MB.