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利用阴离子交换膜电解方法制备了La(OH)3。研究了电极材料、电流密度、反应介质对La(OH)3的影响。使用不锈钢材料作阴极,在电流密度低于300 A.m-2时,La(OH)3质量随电解时间线性增大。较佳工艺条件为:电流密度300 A.m-2,LaCl3浓度为0.2 mol.L-1,添加剂浓度为15%。循环伏安曲线表明,电解过程中不锈钢表面氧化膜和H+的还原均有一个电流阶跃,两个阶跃间有一个相对平缓的电流区域。相同电压时,无添加剂的0.2 mol.L-1LaCl3溶液电流最大,含15%添加剂时的电流下降,0.6 mol.L-1NaCl空白溶液的电流最小。La(OH)3的生成使析氢电位正移。
La (OH) 3 was prepared by anion exchange membrane electrolysis. The effects of electrode material, current density and reaction medium on La (OH) 3 were studied. Using stainless steel as cathode, the mass of La (OH) 3 linearly increases with the electrolysis time when the current density is lower than 300 A.m-2. The optimum conditions were: current density 300 A.m-2, LaCl3 concentration 0.2 mol.L-1 and additive concentration 15%. The cyclic voltammetry curves show that there is a current step in the reduction of oxide film and H + on stainless steel during electrolysis, and a relatively flat current region between the two steps. At the same voltage, the current of 0.2 mol.L-1LaCl3 without additives was the largest, the current with 15% of additives decreased, and the current of 0.6 mol.L-1NaCl blank solution was the lowest. The formation of La (OH) 3 shifts the hydrogen evolution potential to positive shift.