几种多孔电极材料镓电沉积性能的研究
关键词:
金属镓,
电沉积,
泡沫金属,
多孔碳,
电流效率
Abstract: Ga is usually extracted from alkaline solution with low Ga concentration by electrodeposition method in industry, where the hydrogen evolution side reaction and low mass transfer rate are the main reasons for the low current efficiency. In this work, three-dimensional porous electrodes were applied for Ga electrodeposition on account of their high surface area. The hydrogen evolution characteristics of the different electrode materials (foam metal and porous carbon) were studied. And on this basis, Ga electrodeposition behavior of each material under different electrolysis temperatures and current density was researched. The results showed that Cu foam and graphite felt (GF) had low hydrogen evolution activity, but the electrodeposition performance of Ga on the two electrodes was very different. The current efficiency (QE) of Cu foam at 40℃ and 0.1 A/cm2 was 22.5%, which was much higher than that of Cu plate (10.7%). Under the same conditions, the QE value of GF electrode was only 9.6%, which was lower than that of Cu plate and would be related to the hydrophobicity of the electrode surface. The electrodeposition behavior of Ga on electrodes with high hydrogen evolution activity (Fe foam, Ni foam, and reticulated vitreous carbon) was greatly affected by electrolysis temperature and current density. At high current density, the Fe foam electrode showed a QE value only second to that of Cu foam, and Ga electrodeposition was difficult to occur at low current density. The electrodeposition of Ga occurred only below the melting point of Ga (20℃) at Ni foam and reticulated vitreous carbon (RVC) electrodes, but it was difficult to occur at 40℃ above the melting point of Ga due to the high activity of the electrodeposited liquid Ga. Therefore, the hydrogen evolution activity of the electrode materials had a great influence on Ga electrodeposition. The key factors affecting the current efficiency of Ga electrodeposition included electrolysis temperature, current density, and hydrophilicity of the electrode surface.
Key words:
Metal Ga,
Electrodeposition,
Foam metal,
Porous Carbon,
Current efficiency