Research On Electrochemical Sensing And Electrocatalytic Water Splitting Based On Metal Nanocomposites

At present,the application of electrocatalytic materials in industry,environment,food,disease prevention and other fields have attracted more and more researchers'attention.Among them,nanocomposites have become one of the hot research fields of electrochemistry and electrochemical sensing due to their excellent conductivity and excellent synergistic electrocatalytic performance.In this dissertation,three nanocomposites of Pt Ni Cu,Ni₅₀Co₅₀(OH)₂/BO_X and Fe(OH)₂/HCO₃^-were prepared,and two electrochemical sensors based on Pt Ni Cu and Ni₅₀Co₅₀(OH)₂/BO_X were constructed,respectively.The relationship between the morphology,composition,size,electrocatalytic performance of the nanocomposite at the sensor interface and the response performance of the sensor has been studied,and thus the novel electrochemical sensing methods for the detection of glucose,catechol and hydroquinone have been established.We also use Fe(OH)₂/HCO₃^-in the research of electrolytic water splitting.This research provides a new method for the analysis of glucose and benzene isomers,and enrich the phase research content of electrocatalytic water splitting.Full text can be divided into four chapters,and the author's main contributions are listed as follows:1.The Ni₅₀Co₅₀(OH)₂/BO_X composite material was prepared by a one-step method and coated on the surface of the FTO to construct a new electrochemical method for glucose detection.The morphology,composition and size of the material have been studied by Scanning electron microscopy(SEM),Transmission electron microscopy(TEM),Energy dispersive spectroscopy(EDX),X-ray photoelectron spectroscopy(XPS),X-ray diffraction spectroscopy(XRD),Raman spectroscopy.The results showed that the prepared Ni₅₀Co₅₀(OH)₂/BO_X is a network structure containing particles having size of 50 nm,which are connected with each other.The results of electrochemical experiments showed that the new glucose electrochemical sensing method has a good linear range of 0.005-10.83 m M,high sensitivity of 927.3?A m M^-1 cm^-2,and low detection limit of 0.02?M.It can also be applied to glucose detection in human blood serum samples.Compared with similar sensing methods,the sensitivity of this method is increased by 1.7 times,and the linear range is expanded by 1.3 times.The results of electrochemical experiments showed that the linear range of the new electrochemical sensing method for catechol is 5-350?M and 350-3000?M,the sensitivity is 1485?A m M^-1 cm^-2,and the detection limit is 0.4?M.Compared with similar sensing methods,the linear range of this method is increased by 12 times,and the detection limit is reduced by 1.6 times;the linear ranges of the established new hydroquinone electrochemical sensing method are 5-350?M and 350-2900?M.The sensitivity is 1515.55?A m M^-1 cm^-2,and the detection limit is 0.5?M.Compared with similar sensing methods,the linear range of this method is increased by 9.3 times.2.Fe(OH)x/HCO₃^-/FTO was prepared on the surface of FTO by the colloidal method,and further calcined at different temperatures to prepare Fe(OH)x/HCO₃^-FTO₂₅₀ and Fe(OH)x/HCO₃^-/FTO₅₀₀,which were used for water splitting electrocatalysis.The results obtained by SEM,EDX,XRD and XPS showed that the above three materials have been successfully prepared.Among them,Fe(OH)x/HCO₃^-/FTO is flakes gathered together(400-800 nm);Fe(OH)x/HCO₃^-FTO₂₅₀ is a microtube or block with a length of about 500 nm and a width of about 200 nm.The overlapping network structure of Fe(OH)x/HCO₃^-/FTO₅₀₀was observed due to irregular block(from 500 nm to 800 nm).The results of studying on electrocatalytic water splitting in composites show that Fe(OH)x/HCO₃^-/FTO has good oxygen evolution reaction activity,with an onset potential of less than 1.55V(vs.RHE),and its Tafel slope is as low as 36 m Vdec^-1,the charge transfer resistance is negligible,showing excellent electrical activity in long-term electrochemical experiments;Fe(OH)x/HCO₃^-/FTO₂₅₀,the onset potential is less than 1.52V(vs.RHE),the Tafel slope is 59 m Vdec^-1;Fe(OH)x/HCO₃^-/FTO₅₀₀,starting potential is less than 1.54V(vs.RHE),Tafel slope is 89m Vdec^-1.Compared with the other two catalysts,the uncalcined Fe(OH)₂/HCO₃^-has the best catalytic effect on water splitting.