| Two-dimensional planar graphitic carbon nitride(g-C3N4)has been a good candidate for high catalytic active nanocomposites owing to its unique chemical and thermodynamics stability,highly delocalized ? conjugated system,structural defects of large holes and proper location of valance band and conduction band.They are usually used as catalys due to the several active centers including the center of the alkali,the acid centers and single-electron properties on the alkaline earth metal SrO.The synergies gained from the compound will be suit for electroanalytical oxidate.In addition,SrTiO3 and PbTi03 with perovskite structure are of unique loose and multilayer structure.In order to reach the excellent electrocatalysis to vanillin and BPA respectively,the highly active facets were grown oriented by controlling the reaction conditions.A series of works had been completed as follows.1.Bulk g-C3N4 was synthesized by calcining melamine and then exfoliated into a two-dimensional layered structure using chemical method.SrO nanoparticles were anchored on mg-C3N4 nanosheets to form SrO/mg-C3N4 by reduced agent of NaBH4 in the mixture of absolute alcohol and isopropyl alcohol.A vanillin sensor was synthesized by glassy carbon electrode modified with SrO/mg-C3N4.Due to the conjugation effect between SrO nanoparticles with mg-C3N4,the separated ability and efficiency of charge about electron-hole were enhanced,which improved the response current and sensitivity of the composite with a wider linear range of 0.02?180?M and a detection limit of 6.7×10-8M,which is attributed to the active site of alkali in the surface of SrO.According to the relationship of scanning speed and response value of current,it was indicated that vanillin was attached on electrode by a process of adsorption in controlled and two electrons was transferred in this process.The experiment result was identified by the sample of milk in practice.2.Tetrabutyl titanate and strontium nitrate are the source material.The titanium was synthesized by tetrabutyl titanate rapidly with the addition of KOH and the crystal nucleus of SrTiO3 were formed attribution to the Sr ions migrated into the titanium colloids.The crystal nucleus grows along with the(110)facet with SrTiO3 crystals.After slow process of Ostwald maturity,the uniform SrTiO3 crystal with the morphology of cube was synthesized.With the SrTiO3 modified electrode,the sensor shows the excellent electrocatalytic property of the concentration range from 3.0×10-6 to 1.5×10-4M,a higher sensitivity of 56.2?A/mM and a lower detection limit of 6.0×10"7M.According to the result,a mechanism was introduced.The Sr in the SrTiO3 crystal is benifited to combine the hydroxyl of water and organic molecular to form the active site of oxidation reaction in the electrochemical test,which plays an important role in the electrocatalysis of vanillin.In addition,the sample of milk was also detected in the experiment.3.The source material of tetrabutyl titanate and lead nitrate were formed coprecipitation in controlled with pH.After the magnetic stirring,the metastable middle phase of Ti-O octahedron was formed at first.The.Pb ions diffused into the Ti-O octahedron to form the stable PbTiO3 crystal nucleus under the condition of 200?.The crystal nucleus grew along with the(330)facet gradually and finally the cuboid PbTiO3 crystal was synthesized.The sensor displayed the excellent property of electrocatalytic bisphenol A with a linear response over the concentration range from 3.0×10-6 to 2.0×10-4M,a higher sensitivity of 11.3?A/mM and a lower detection limit of 9.0×10-7M by the electrode modified with PbTiO3,which depends on the structure of cuboid PbTiO3 crystal.The loose structure of the cuboid PbTiO3 crystal is beneficial to the formation of oxygen ion vacancy,which is very effective to the electrocatalytic oxidation of the hydroxyl in bisphenol A.The BPA in the sample of plastic origin from the market was also test in practice. |
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