Influence of sodium silicate on manganese electrodeposition in sulfate solution

硅酸钠对硫酸盐溶液中电沉积锰的影响（英文）

The influences of sodium silicate on manganese electrodeposition in sulfate solution were investigated. Manganese electrodeposition experiments indicate that a certain amount of sodium silicate can improve cathode current efficiency and initial pH 7.0?8.0 is the optimized pH for high cathode current efficiency. The analyses of scanning electron microscopy (SEM) and X-ray diffraction (XRD) indicate the compact morphology and nanocrystalline structure of electrodeposits. X-ray photoelectron spectrometry (XPS) analysis shows that the elements of Mn, Si and O exist in the deposit. The solution chemistry calculations of sulfate electrolyte and sodium silicate solution indicate that species of Mn2+, MnSO4, Mn(SO4)2?2 , Mn2+, MnSiO3, Mn(NH3)2+, SiO32?and HSiO3? are the main active species during the process of manganese electrodeposition. The reaction trend between Mn2+ and Si-containing ions is confirmed by the thermodynamic analysis. In addition, polarization curve tests confirm that sodium silicate can increase the overpotential of hydrogen evolution reaction, and then indirectly improve the cathode current efficiency.

研究硅酸钠对硫酸盐溶液中锰电沉积的影响。锰电沉积实验结果表明,添加一定量的硅酸钠可以提高锰电沉积的阴极电流效率,且初始pH 7.0~8.0是获得较高阴极电流效率的pH优化值。扫描电子显微镜(SEM)和X射线衍射(XRD)分析结果表明,所得电沉积层呈致密、纳米晶结构。X射线光电子能谱(XPS)分析结果表明,电沉积层中含Mn、Si和O元素。硫酸盐溶液和硅酸钠溶液化学计算结果表明,在锰电沉积过程中,Mn^(2+)、MnSO_4、Mn(SO4)_2^(2-)、Mn^(2+)、MnSiO_3、Mn(NH_3)^(2+)、SiO_3^(2-)和HSiO_3^-是主要的活性组分。Mn^(2+)与含硅离子的反应趋势经热力学计算分析证实。此外,极化曲线测试结果表明,添加硅酸钠可以提高析氢过电位,从而间接提高了阴极电流效率。