Study Of Electrodeposition Of Nickel And Copper Two Component Metals By Bipolar Electrochemistry

As a kind of functional materials,the gradient alloys have gradually become a hot research topic in synthetic technologies and applications.The research contents of this thesis include two aspects.First,Ni_xCu_1-x alloys with composition gradient were electrodeposited based on bipolar electrochemistry,to study the morphology evolution and electrocatalytic effect;second,according to the principle of bipolar electrodes,a bipolar electrolytic cell was self-made,to explore detection and separation of metal ions?Ni?Cu?by online bipolar electrode method.Bipolar electrodeposition was used to fabricate Ni_xCu_1-x gradient alloys on copper substrates,based on an in-plane potential gradient over the interface of a bipolar electrode?BPE?and an electrolytic solution.The position-dependent deposition rates of Cu and Ni generated a composition gradient for the deposits along the surface of the BPE.The alloys deposited on a single BPE contained from 0 to ca.89% Ni atoms,with abundant morphology evolution from pyramids to dendrites and to nano/microballs in different positions of the BPE,as characterized using scanning and transmission electron microscopy techniques.Electrochemical screenings were performed for the dissected alloy specimens as electrocatalysts of hydrogen evolution reaction,by using cathodic scan polarization,chronopolentiometry and EIS methods.The electrocatalytic activity of the alloys is highly dependent on the composition and morphology.The best electrocatalytic activity to the HER was always achieved on the alloy with a Ni content of 61%.This work shows that bipolar electrochemistry can provide a highly efficient way to fabricate alloys with abundant architectures as high throughput screening candidates.On the basis of the principle of bipolar electrode electrochemistry,a fluidic bipolar electrolytic cell was designed and fabricated,for the separate deposition of two pure metals Ni and Cu on a split bipor electrode from the mixed solutions of Ni²⁺ and Cu²⁺.This strategy may be used for the online separation and detection of heavy metal ions.A lot of exploratory experiments have been carried out,to study the effect of bipolar electrode material,driving voltage,flow velocity of the solution and the distance between the two driving electrodes.According to the problems in the experiment,we constantly optimize the structure of bipolar electrode electrolysis device,and solve a series of problems,such as poor sealing performance,uneven flow rate and difficult injection of sample solution.The improved separation bipolar electrode electrolyzer has the advantages of simple processing program,controllable structure,flexible operation and so on.However,combined with the i-t curve tested by electrochemical workstation,it can be seen that adjusting the driving potential or hose length does not rapidly separate single metal ions and two-component metal ions,and the location of metal ions on the bipolar electrode cathode is always near the end.Therefore,it is necessary to explore and study the problems that exist in the experiment.We need to go deep into the data to understand the electric field distribution in the microchannel,and design a reasonable separate bipolar electrode electrolysis cell,so as to successfully separate two component heavy metal ions online.In conclusion,the Ni_xCu_1-x composition gradient alloy can be successfully prepared by bipolar electrode electrodeposition,and it can be used as a high flux electrocatalyst material.The bipolar electrode is combined with the electrochemical workstation.The i-t method is used to record the current changes in the separation process.This creates a new method of detection and separation.