Electrodeposition Of Electrode Materials （Ag₃PO₄、AgCuO₂） In Amnonia-Coordinated System And Their Performance

With the growing of energy problem and the frequent occurrence of bad weather such as haze, solar cars and electric vehicles are becoming more and more popular as alternative fuel vehicles. At the same time, potable electric mobile devices have become the mainstream of life. Therefore, developing efficient energy conversion materials or equipment has become the key to solving the energy and environmental problems. Semiconductor-based materials and efficient battery materials are two main kinds of energy conversion materials. In this paper, we used the visible-light-responding semiconductor Ag₃PO₄ and cathode material AgCuO₂ as research objects, focusing on the preparation mechanism of these two materials through electrodeposition in solution containing NH₃·H₂O as the ligand. The properties of the prepared materials are also characterized. The main contents and results are as follows:（1） ITO-based Ag₃PO₄ thin film was prepared by anodic oxidation through potentiosatic electrodeposition at room temperature in AgNO₃ solution containing NH₃·H₂O as the complexing agent of Ag⁺. By calculating the disctrubution diagram at different pH of Ag-NH₃ system, CV tests and UV-Vis spectroscopy tests of the oxidation products, we found that the oxidation of NH₃·H₂O occurred during the oxidation of H₂O during the electrodeposition, which promoted the release of Ag⁺from Ag（NH₃）₂⁺ and accelerated the deposition of Ag₃PO₄ thin film. The possible mechanism was summarized. In addition, the structure, composition and morphology of Ag₃PO₄ were characterized by XRD, SEM and EDX. The effect of different deposition potentials on the orientation and morphology of Ag₃PO₄ were also discussed. The results show that Ag₃PO₄ electrodeposition process is controlled by the kinetic model. At higher potentials （1.6V vs. Ag/AgCl）, an independent crystal of tetrahedron with{111} high energy surface can be obtained. Under visible light irradiation, Ag₃PO₄ electrode in Na₃PO₄ solution （pH= 7） can produce lasting and stable photocurrent.（2） ITO-based AgCuO₂ nanosheets were elecrodeposited at a constant current density of 20mA/cm² in a mixed solution of AgN0₃ and Cu（NO₃）₂ at strong base conditions containing NH₃·H₂O as the complexing agent of Ag⁺ and Cu²⁺ near room temperature. It was found that the ammonia complex in the solution had an electrocatalytic effect on the oxidation of NH₃ and H₂O, which further promoted the decrease of pH value on the surface of the electrode, and the free Ag⁺ and Cu²⁺ were electrochemically oxidized and co-deposited on ITO. The possible mechanism was summarized. In addition, the composition and structure of AgCuO₂ crystal were characterized by tests of XRD, SEM, SAED and TG and so on. The results show that the AgCuO₂ was of single crystal structure. In the meantime, the XPS results show that there exists charge delocalization among the atoms of AgCuO₂, and Ag and Cu are partly oxidized to +3 valence state. In the discharge test of AgCuO₂ electrode, there are four distinct discharge stages, and the specific capacity of the initial one-electron discharge accounts for 77% of the theoretical value.