The Study Of The Oscillation And Its Time Delay Control In Copper Anodic Dissolution In Phosphoric And Sulphuric Acid

The study of electrochemical oscillations can make us know the mechanism of electrochemical reactions and the research of coupling and synchronization of electrochemical oscillations make us realize that different oscillations can be made by two work electrodes acting each other. The study of chaos control in electrochemical oscillations can not only combine the research of chemistry and chaos, but also improve electrochemical reactions. There are abundant oscillations in electrochemical system with copper being the anode. These years, there are many reports of the study of Cu/H3PO4 system. We can know further the mechanism of the anodic dissolution of copper by studying the influence of additives put into the above system. There is no report about the influence of H3PO4, a special additive, on Cu/H3PO4 system. In this paper, the anodic dissolution of copper in phosphoric and sulphuric acid was studied.Through sweep voltammograms, we study the results of changing the rate of sweep, temperature, electrodes of different shapes and connecting a resistance .We pay much more attention to the influence of H2SO4.It is found that the oscillation is the result of the breaking and forming of film coupling with the mass transport. It also shows that the oscillation amplitude increases at first, then decreases gradually with the increase of the amount of H2SO4 addition.We find many types of oscillations during the experiments. Compared with the system without additive, there are more kinds of oscillations with H2SO4 as additive in the experiments.Means of the delay feedback is used to control the chaos in the electrochemical oscillations during the process of the anodic dissolution of copper. The result proved that the method is effective. We control the chaos to period and control the period one to period two and period four. We also study the effect of the control-factors.Last, we study the coupling and synchronization of electrochemical oscillations. The results show that the synchronization is determined by mass transport. With suitable amount of H2SO4 put in the system, there are more 1:1 synchronizations discovered.