Fabrication And Properties Of Electrochemical Sensors Based On Binary Metal Oxides (Phosphides) Nanoarrays

In this dissertation,various hybrid nanostructures based on Ni?OH?₂ nanoflake arrays and ZnO nanorod arrays were fabricated and utilized as substrate to construct electrochemical sensors.The overall performance of glucose electrochemical biosensors based on NiO/Fe₂O₃ nanocomposites was improved,which attributed to the synergistic effect of the metal oxide hybrid nanostructures.Meanwhile,ZnO/CeO_2-x-x hybrid nanorod arrays and Ni₂P/InP nanoflake arrays were also fabricated and employed to construct electrochemical sensors for H₂O₂ detection at negative working potential,in order to obtain the substrate materials of electrochemical sensor with good anti-interference ability.The main researches and results are described follows.Firstly,Ni?OH?₂ nanoflake arrays supported on Ni foam were synthesized by hydrothermal method and they were used as the substrate to fabricate NiO/Fe₂O₃nanocomposites by two-step hydrothermal process in combination with calcinations.After optimizing parameters of hydrothermal reaction,NiO/Fe₂O₃ nanocomposites were obtained and utilized to construct glucose biosensors by cross-linking method.The as-prepared biosensors achieved a high sensitivity of 230.5?A·cm^-2·mM^-11 due to the synergistic effect between NiO and Fe₂O₃ and exhibited acceptable selectivity toward detection of glucose concentration for diabetics.Secondly,ZnO nanorod arrays were synthesized through electrochemical deposition approach and were used as the substrate in the following hydrothermal reaction.ZnO/CeO_2-x-x nanorod arrays were finally fabricated after calcination treatment in Ar-atmosphere.Owing to the presence of oxygen vacancies in CeO₂,Ce³⁺formed and CeO_2-x-x exhibited reducibility towards H₂O₂,ZnO/CeO_2-x-x nanorod arrays showed electrocatalytic activity to H₂O₂(the sensitivity is 63.5?A·mM^-1·cm^-2)and good selectivity at a low potential of-0.4 V.Finally,InP/Ni₂P nanoflake arrays were synthesized based on the as-prepared Ni?OH?₂ nanoflake arrays in combination with phosphidation and used to detect H₂O₂.The results showed that InP/Ni₂P nanoflake arrays presented good response to H₂O₂ at a low potential of-0.4 V and the sensitivity achieved 150.2?A·mM^-1·cm^-2.InP/Ni₂P nanoflake arrays could be employed as the substrate for electrochemical biosensors based on oxidase after further improving its sensitivity by tailaring the microstructure.