氯化胆碱-尿素体系中电沉积Ni-Fe-Sm析氢催化电极研究

Study on electrodeposition of Ni-Fe-Sm catalytic electrode for hydrogen evolution in choline chloride-urea system

采用恒电位电沉积技术,在氯化胆碱-尿素体系中制备Ni-Fe-Sm/Cu稀土合金电极并研究其析氢(HER)性能。通过阴极极化曲线(LSV)、循环伏安曲线(CV)等电化学测试方法及SEM等表征技术,研究沉积条件对稀土合金电极的析氢性能及其表面形貌的影响。结果表明,添加稀土元素Sm能够有效提升合金电极的析氢性能。在-1.22 V的沉积电位下,沉积20 min制备的Ni-Fe-Sm/Cu稀土合金电极析氢性能最佳。在10 mA/cm^(2)电流密度下,稀土合金电极的析氢过电位仅115 mV,Tafel斜率最小,析氢反应受Volmer-Heyrovsky反应控制。且该条件下制备的Ni-Fe-Sm/Cu稀土合金具备最高的双电层电容,电催化活性表面积最大。通过交流阻抗法(EIS)可知,Ni-Fe-Sm/Cu合金电极具有较高电荷转移速率。此外,Ni-Fe-Sm/Cu稀土合金电极在碱性介质中具有较好的稳定性,在经过1000圈的循环侧安测试,电催化析氢性能没有明显变化。

The Ni-Fe-Sm/Cu rare earth alloy electrode was prepared by potentiostatic electrodeposition in choline chloride-urea system and its hydrogen evolution(HER)performance was investigated.The effects of deposition conditions on the hydrogen precipitation performance of rare earth alloy electrodes and their surface morphology were investigated by LSV,CV and SEM.The results show that the hydrogen evolution performance of the alloy electrode was improved by the addition of rare earth element Sm.The optimal preparation conditions were deposited at a deposition potential of-1.22 V for 20 min.At a current density of 10 mA/cm^(2),the hydrogen evolution overpotential of the Ni-Fe-Sm/Cu alloy was only 115 mV and the Tafel slope was the smallest.The hydrogen evolution reaction was controlled by the Volmer-Heyrovsky reaction.The Ni-Fe-Sm/Cu alloy had the highest electric double layer capacitance and the largest electrocatalytic active surface area.The Ni-Fe-Sm/Cu alloy electrode showed a higher charge transfer rate by the AC impedance method(EIS).In addition,the Ni-Fe-Sm/Cu rare-earth alloy electrode showed good stability in alkaline media.1000 sweeps of cyclic voltammetry were conducted and no obvious change was observed.