石墨电极上电沉积钯镍合金的循环伏安研究

An Investigation of the Cyclic Voltammetry of Electro-deposition of Pd-Ni Alloy on Graphite Electrode

用循环伏安法对NiSO4 与PdCl2 混合溶液合成钯镍合金纳米线的电化学沉积条件进行了研究 .结果表明 ,钯镍离子混合液中钯的析出对镍、氢的电极过程有很强的去极化作用 ,使镍的析出电势正移 ,减小了钯、镍析出电势的差距 .钯离子浓度为 2mmol·L- 1,镍离子浓度为 0 .32mol·L- 1时 ,有利于形成钯镍合金 .高超电势和大电流密度下可以实现钯、镍共沉积 .但高浓度和高超电势下 ,电沉积的电流密度大 ,使金属的沉积速度过快 ,不利于形成钯镍合金纳米线 .钯镍析出电势相差较大 ,在低超电势条件下 ,难于实现共沉积 ,需通过加入添加剂或络合剂等其它方法来改变钯、镍的析出电势 ,使二者析出电势更进一步接近以达到共沉积的目的 .

Cyclic Voltammetry (CV) was used to study the electrochemical conditions in order to synthesize nanowires of Pd-Ni alloy in the mixtures composed of PdCl 2 and NiSO 4. The results revealed that the palladium deposited from the mixture of PdCl 2 and NiSO 4 could reduce the polarizations of the electrode process of producing Ni and H 2. The depolarization makes the deposit potential of Ni move positively, which reduces the deposit potential difference between Pd and Ni. The mixture of 2 mmol·L -1 PdCl 2 and 0.32 mol·L -1 NiSO 4 is favorable for the formation of the structure of Pd-Ni alloy. Under the condition of large over-potential and high current density, Pd and Ni can be co-deposited, but under the condition of high ion concentration and large over-potential, the high current density causes a fast deposit rate, which is disadvantageous to the deposition of the nanowires of Pd-Ni alloy. It is difficult to realize the co-deposition of Pd and Ni at the low over-potential with a great difference of deposit potentials between Pd and Ni. It is necessary to search for other methods, such as affiliating some complex agents or suitable additives, etc, to change the deposit potentials of Pd and Ni, so as to make their deposit potentials much closer to each other and to realize the co-deposition of Pd and Ni.