Fabrication Of TiO₂/Nitrogen-doped Graphene Nanomaterials And Their Applications In Photoelectrochemical Sensing Of Organic Pollutants

In this essay,TiO₂/nitrogen-doped graphene?Ti O2/NG?and TiO₂/three-dimensional nitrogen-doped graphene?TiO₂/3DNG?with excellent photoelectrochemical?PEC?performances were fabricated and then the two different nanomaterials were modified on two sensor interface,the two established PEC sensors were used for the detection of bisphenol A?BPA?and chlorpyrifos respectively;besides,TiO₂/borocarbonitrides?TiO₂/BCN?nanosheets were also fabricated and combined with aptamer for the successful detection of BPA.The main steps of the experiments were as follows:1.The TiO₂/NG nanomaterials were prepared by one-step thermal-treatment method,and characterized by various routes.According to the research,the introduction of NG can promote the dispersion and the size of nanoparticles,enlarge the photocurrent to 3 times of pure TiO₂,promote the separation of photoinduced electron-hole,improve the speed of the charge transfer on the interface,expand the absorption to the light.Combining BPA aptamer,based on the photocurrent enhancement responding to the BPA,a PEC biosensor was established for BPA detection.Under the optimal condition,the PEC platform displayed a wide linear range from 1 fmol/L to 10 nmol/L and low detection limits of 0.3 fmol/L?S/N = 3?,and the fabricated bisensor exhibited an excellent stability,selectivity and sensitivity,can be used for the analysis of drinking water and milk in our life.2.The three-dimensional TiO₂/NG?TiO₂/3DNG?were prepared by one-step solvethermal treatment method,and characterized by various routes.According to the research,the introduction of NG can enlarge the photocurrent to 5 times of pure TiO₂,promote the separation of photoinduced electron-hole,improve the speed of the charge transfer on the interface,expand the absorption to the light.Based on the photocurrent enhancement responding to the chlorpyrifos,a PEC biosensor was established for chlorpyrifos detection.When the concentration of chlorpyrifos ranged from 5 ?g/mL to 0.25 g/mL,the enhancement of corresponding photocurrent existed a linear relationship with the logarithm of the chlorpyrifos concentration,and theobtained detection limit is 1.7 ?g/mL?S/N = 3?.The fabricated bisensor exhibited an excellent stability,selectivity and sensitivity,can be used for the analysis of drinking water in our life.3.The TiO₂/BCN nanomaterials were prepared by one-step thermal-treatment method,and characterized by various routes,the nanomaterials possess nanosheets structure,and TiO₂ nanoparticles were distributed on the regularly.The research indicates that the introduction of BCN can enlarge the photocurrent to 2 times of pure TiO₂,promote the separation of photoinduced electron-hole,improve the speed of the charge transfer on the interface,expand the absorption to the light.Due to the enhancement of photocurrent response to the addition of BPA,the platform containing PEC material and aptamer were fantabulously established for BPA detection.When the density of BPA ranged from 0.1 fmol/L to 5 nmol/L,the enhancement of corresponding photocurrent existed a linear relationship with the logarithm of the BPA concentration,and the obtained detection limit is 0.033 fmol/L?S/N = 3?.The fabricated bisensor exhibited an excellent stability,selectivity and sensitivity,can be used for the analysis of drinking water and milk in our life.