Synthesis And(Photo)electrochemical Determination Properties Of Ti-based Nanocomposite Arrays

In recent years,resource shortage and severe environmental pollution have not only become a major challenge to the sustainable development of Chinese economy and society,but also pose a huge threat to human health.Environmental pollution and health problems have become two issues of great concern to the broad masses of the people.Advanced detection technique is the prerequisite condition to protect the environment and control pollution.Rapid and highly sensitive detection technology can not only guarantee the safety of the public,but also has important significance for studying the impact of environmental pollutant exposure on the health of the population.At present,there are many ways to detect target substances in vivo and in vitro environment.Electrochemical methods are extremely useful techniques for environmental analysis due to their simplicity,reliability,low energy consumption,high selectivity and high sensitivity.In this thesis,systematic studies on the synthesis,characterization,and（photo）electrochemical properties of Ti-based nanocomposite arrays including TiC@C,TiC@CNx,and Au/TiO_2-x@C nanofiber arrays（NFAs）on constructive substrates have been presented.A highly sensitive and selective sensor for dopamine and Cr（Ⅵ）determination has been developed based on the TiC@CNx NFAs.And a new integrated platform based on Au/TiO_2-x@C NFAs has been constructed for simultaneous photocatalytic removal and online electrochemical monitoring of Cr（Ⅵ）ion in water and real samples.The influence of nanoarrays’morphology,chemical composition,microstructure on the photocatalytic degradation and electrochemical performance toward analytes have been systematically investigated.The main results are summarized as follows:1.Core-shell TiC@C and TiC@CNx NFAs fabricated on Ti-6Al-4V consist of highly conducting TiC cores and electrochemically active carbon shells or N-doped carbon shells.N doping endows the TiC@CNx NFAs with enhanced electrochemical properties such as fast heterogeneous electron transfer in the[Fe（CN）₆]^3-/4-redox couple and high activity in simultaneous and selective detection of dopamine（DA）,ascorbic acid（AA）,uric acid（UA）,and serotonin（5-hydroxytryptamine,5-HT）as well as high sensitivity and selectivity in the determination of DA in the presence of UA,AA,and 5-HT.The linear range for the determination of DA is 0.5-180μM and detection limit is 8nM（S/N=3）.2.Study on the detection performance of TiC@CNx for the heavy metal pollutants Cr（Ⅵ）ion.TiC@CNx electrode was used for selective monitoring of Cr（Ⅵ）in industrial wastewater in the presence of other interfering metal ions.The current response of Cr（Ⅵ）from TiC@CNx electrode is larger than 10 times from that of the bare glassy carbon electrode,indicating the high sensitivity of the TiC@CNx electrode.The linear range for the determination of Cr（Ⅵ）is 0.2-46.1μM and detection limit is 44nM（S/N=3）.3.C,Au and TiO₂ integrated functional(Au/TiO_2-x@C)NFAs were prepared on conductive carbon cloth substrate using hydrothermal,hydrogeneration,and electrodeposition methods,which have not only excellent photocatalytic activities for degradation of Cr（Ⅵ）but also outstanding electrochemical activities for determination of Cr（Ⅵ）,has been achieved.The NFAs compose of highly photocatalytic oxygen vacancies（OVs）contained TiO₂ species and highly electroactive materials including carbon nanomaterials and Au nanoparticles.The excellent photocatalytic and electrocatalytic properties of Au/TiO_2-x@C offers it to completely reduce 120μM Cr（Ⅵ）to Cr（Ⅲ）with in 24 min,and simultaneous electrochemically monitor the residual concentration of Cr（Ⅵ）.