La掺杂的SnO2-Sb中间层对钛基IrO2+Ta2O5电极性能的影响

目的改善Ti/IrO_2+Ta_2O_5涂层电极的析氧电催化性能。方法用热分解法在钛基材上制备了La掺杂的SnO_2-Sb中间层,并以此作为基体涂覆IrO_2+Ta_2O_5活性层,制备了Ti/SnO_2-Sb-La/IrO_2+Ta_2O_5涂层电极。采用扫描电子显微镜(SEM)、能量散射能谱(EDS)及X-射线衍射光谱(XRD)技术分别分析了中间层和活性层的表面形貌、元素组成及晶相结构。采用线性扫描伏安曲线(LSV)和强化寿命测试方法在硫酸溶液中分别研究了Ti/SnO_2-Sb-La/IrO_2+Ta_2O_5涂层电极的析氧电催化活性和使用稳定性。同时,考察了La的掺杂比例对Ti/SnO_2-Sb-La/IrO_2+Ta_2O_5电极强化寿命的影响。结果相对未掺杂La的中间层,掺杂La后的中间层表面裂纹减少,有更高的析氧过电位和更低的析氧电流密度。La掺杂对活性层的表面形貌和晶相结构基本没有影响,但电极的析氧电流密度有所提高。通过测试不同La掺杂比例涂层电极的强化寿命,发现La最佳掺杂比例为nLa:nSn=0.5:100。和未掺杂La涂层相比,La最佳掺杂比例涂层电极的强化寿命提高了22.8%。结论相对于未掺杂的Ti/SnO_2-Sb/IrO_2+Ta_2O_5电极,La掺杂后的Ti/SnO_2-Sb-La/IrO_2+Ta_2O_5涂层电极析氧电催化活性和强化寿命都得到改善。

Effect of La-doped SnO2-Sb Interlayer on Properties of Ti/IrO2+Ta2O5 Electrode

The work aims to improve O2 evolution electrocatalytic property of Ti/IrO2+Ta2O5 coating electrode. La-doped SnO2-Sb interlayer prepared on Ti substrate in pyrolytic process was coated with IrO2+Ta2O5 active coating to prepare Ti/SnO2-Sb-La/IrO2+Ta2O5 electrode. Morphology, elemental composition and crystal structure of the interlayer and active layer were analyzed with scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS) and X-ray diffractometer (XRD), respectively. The electrocatalytic activity and operational stability of the Ti/SnO2-Sb-La/IrO2+Ta2O5 electrode for O2 evolution in H2SO4 solution were investigated with linear sweep voltammetry (LSV) curve and accelerated life test, respectively. Additionally, effects of La doping ratio on accelerated life of Ti/SnO2-Sb-La/IrO2+Ta2O5 electrode were investigated. Compared with SnO2-Sb interlayer undoped with La, the La-doped SnO2-Sb interlayer had less cracks, higher overpotential for O2 evolution and lower current density for O2 evolution, and La doping had slight effect on the morphology and phase structure of the active layer, but obviously improved the current density of the electrode for O2 evolution. By performing accelerated life test to the electrodes doped with different ratios of La, the best doping ratio was nLa: nSn=0.5:100. The accelerated life of coating electrode doped with best La ratio increased by 22.8% than that undoped with La. In conclusion, compared with the Ti/SnO2-Sb/IrO2+Ta2O5 electrode, electrocatalytic activity and accelerated life of the Ti/SnO2-Sb-La/IrO2+Ta2O5 electrode for O2 evolution are improved after being doped with La.