The Growth And Characterization Of Electrodeposited Silver Crystal Under Abnormal Electrochemical Conditions

With the development of material science and technology, nanostructured materials with potential application have been paid more and more attention. Among the various means of preparation of nanomaterials, electro-deposition gradually becomes an important method. Silver, for its significant properties in the various areas such as electronics, photonics, catalysis, and so on, becomes research hotspot. Previous research mostly centered on the study of electro-deposition under the traditional conditions. Study on silver electro-deposition under abnormal electrochemical condition without supported electrolytes has usually been ignored. In this paper, study on silver static current electro-deposition on conductive glass plate under abnormal electrochemical conditions has been carried out. The influence of different procedure conditions on the morphology of electrodeposited silver has been discussed. Silver crystal have been characterized by SEM,UV and cyclic voltammetry (CV). The main contents are as follows.The electrode procedure of metals and the mechanism of metal electro-crystallization have been briefly summarized. Process of silver electrodeposition has been reviewed. The theory of fractal, fractal growth during the electro-deposition, and characterization of metal on nanomaterials have been briefly introduced.The impact of PEG1000 and pH values on the appearance of silver electrodeposits has been investigated. The SEM characterization results show that in the AgNO3 aqueous solution with PEG1000, a certain concentration PEG1000 is beneficial to the growth of regular silver polyhedral crystal. Because of the effects of concentration polarization and the change of substrates, several novel appearances of silver electrodeposits were obtained with the certain electro-deposition time and current density.The influence of different process parameters on the profile of electrodeposited silver by static current electro-deposition under abnormal electrochemical conditions has been studied The results show that the morphology of electrodeposited silver crystal clusters was closely associated with the space of the electrodes, the shape of anode, area ratio of cathode and anode, and electrochemical methods. The electrode place pattern not only affects the profiles of clusters, but also affects the size of clusters. Moreover, ripening phenomenon was discovered during the process of silver electro-crystallization under our conditions. X-ray diffractive analysis shows that the silver electrodeposits have face-centered cubic structure.The fractal growth of silver dendrites was preliminarily discussed. The results show that the fractal dimension appears to be fluctuating to a certain extent with the increasement of current density, the concentration of electrolyte, and electro-deposition time, but generally speaking, fractal dimension presents ascending tendency. The products obtained under our experiment conditions have been characterized by UV absorption spectroanlysis. The absorption peak of silver film obtained compared with bulk silver was shifted to blueside. CV characterization shows that the glass electrode modified by electrodeposited nanosilver film has more reducibility than bulk silver electrode.In the PtCI4 aqueous solution with HCI, experiments on platinum electro-deposition on the conductive glass plate have been carried out. Spherical platinum has been prepared. Among a certain range, current density and electrolyte concentration influence the size of particles, but have almost no effects on the morphology of platinum electrodeposits. Experimental results show that nanoplatinum obtained under our conditions has well catalytic activity.