Electrochemical Sensing Research Based On Controllable Synthesis Of Nanomaterials

The properties of nanomaterial,especially its electro-catalytic activity,will be determined by its morphology,composition,structure and size.Therefore,improvement of analytic properties of electrochemical sensor based on controllable synthesis of nanomaterials with high catalytic activity has become one of research hotspots in field of electrochemical analysis,and how to realize controllable synthesis of nanomaterials will be the key point.In this dissertation,eleven kinds of nanomaterials with controllable morphology,size and crystal facet such as MnO2,PdCuCo/GO,Pt/MnO2 were synthesized based on eleven kinds of methods such as regulation of hydrophobic interface,surface modification,etc.Then,eleven kinds of electrochemical sensors were fabricated and new methods of controllable synthesis of nanomaterials and determination of dopamine and other seven kinds of micro-molecules were established.This research provide new platform for controllable synthesis of nanomaterials with highcatalytic activity and research of electrochemical sensing with high properties.The dissertation is divided into five chapters.The author’s main contributions are summarized as follows:1.Electrochemical sensors based on Ag/MnOOH,PANI/MnOOH,Au/PANI/MnOOH and ordered PdCuCo/GO nanomaterials which were synthesized by chemical reduction,in-site polymerization and regulation of templates were fabricated,mechanism of controllable synthesis of nanomaterials and electrochemical and electro-catalytic behaviors were researched,new methods for determination of H2O2,DA,AA were established.The researches indicated that the detection limit of H2O2 electrochemical sensor fabricated based on Ag/MnOOH,DA electrochemical sensor fabricated based on PANI/MnOOH,AA electrochemical sensor fabricated based on Au/PANI/MnOOH and H2O2 electrochemical sensor fabricated based on ordered PdCuCo/GO were 1.5μM,0.01μM and 1.2nM,and the corresponding linear range were 5μM-12.8mM,0.05μM-2.78mM,0.3μM-77.8mM and 5nM-5.774mM,respectively.The four kinds of electrochemical sensors all exhibited broad linear range and compared with the two H2O2 electrochemical sensors,the sensor based on PdCuCo/GO exhibited lower detection limit and broader linear range,and the ordered PdCuCo exhibited better electro-catalytic activity.2.Two kinds of H2O2 electrochemical sensors based on MnO2 nanomaterials which weremodified by formaldehyde and concentrated acid were fabricated.The relationship between electro-catalytic behavior of modified MnO2 and properties of sensor were researched and two kinds of new analytical methods for determination of H2O2 were established.The researches indicated that the catalytic potential,linear range and detection limit of the two kinds of sensors were 0.7V and 0.25V,0.05μM-12.78mM and 0.7μM-1.78mM,0.01μM and 0.02μM,respectively.In contrast,the sensor based MnO2 modified by formaldehyde exhibited broader linear range.However,the other one exhibited lower catalytic potential.Compared with other electrochemical sensor based on non-modified MnO2,the two kinds of sensors all exhibited lower detection limit,broader linear range and more simple modified material,and MnO2 exhibited better electro-catalytic activity after modification.3.Electrochemical sensors based on POSS/GO and Ag/POSS/GO nanomaterials which were synthesized by hydrothermal method and regulation of hydrophobic interface were fabricated.The mechanism of controllable synthesis of Ag nanomaterials and the relationship between hydrophobic force on surface of electrode and properties of sensor were researched,new methods for controllable synthesis of nanomaterials and determination of nitrite and nitrobenzene conpounds were established.The researches indicated that the detection limit and linear range of the first sensor were 0.08μM and 0.5μM-120mM,the detection limit and linear range of the second sensor were 0.1ppm,0.05ppm,0.02ppm and 0.5-155ppm,0.1-77ppm,0.05-330ppm in detection of NB,pNA and pNBA.Compared with other nitrite electrochemical sensors,the first sensor exhibited lower detection limit and broader linear range.For the second sensor,it exhibited the lowest detection limit and the broadest linear range in detection of pNBA which indicated that Ag/POSS/GO exhibited the best electro-catalytic activity for pNBA.Compared with other methods for preparation of Ag nanomaterials,the method exhibited faster reaction time,and aggregation of nanomaterials can be avoided effectively.4.Ag nanoparticles with controlled size and Pt nanomaterials with gravel,gather,globular and cubic morphologies were grown on surface of MnOOH/GO,3D MnO2 and GO.Three kinds of electrochemical sensors based on Ag/MnOOH/GO,3D Pt/MnO2 and Pt/GO which were synthesized by gas/liquid method were fabricated.The mechanism of controllable synthesis of Ag and Pt nanomaterials and the relationship between morphology of nanomaterials and electro-catalytic activity were researched,new methods for controllable synthesis of nanomaterials and determination of H2O2,CH3OH and nitrite were established.The researches indicated that the detection limit of the sensors were 0.2μM,0.05mM and 0.015μM,the linear range of the sensors were 0.5μM-17.8mM,0.125-3219.25mM and 0.05μM-177.78mM.It indicated that Ag/MnOOH/GO,3D Pt/MnO2 and Pt/GO exhibited better electrocatalytic activity and the method for controllable synthesis of Ag and Pt nanomaterials exhibited simple fabricated procedure and better morphology controlled synthesis.In addition,aggregation of nanomaterials can be avoided effectively.