具有高产氢反应催化活性的纳米多孔Ni基合金电极

Nanoporous Ni-based alloy electrodes with high catalytic activity for hydrogen evolution reaction

为制备具有高催化活性的纳米多孔Ni基合金电极用于碱性电解水产氢,首先制备了Ni、NiCo、NiCu和NiFe 4种Ni基合金条带;基于NiCu和NiCo合金体系,利用脱合金化法制备了纳米多孔NiCu和NiCo合金;采用XRD、BET、TEM、LSV等方法分析Ni基合金的晶体结构、形貌结构和电化学性能.结果表明:Ni基合金均为面心立方晶型的单相固溶体;纳米多孔NiCo合金具有均匀的多孔结构,孔径分布为3~6 nm;与原Ni基合金相比,纳米多孔NiCu和NiCo合金的过电势和塔菲尔(Tafel)斜率大幅降低,催化活性明显提高,纳米多孔NiCo合金在电流密度20 m A/cm^2下过电势为140 m V,Tafel斜率为60 m V/dec),接近于Pt.因此,选择具有协同作用的掺杂元素和构建纳米多孔结构是提高Ni基合金电极产氢反应催化活性的有效途径.

To prepare nanoporous Ni-based alloy electrodes with high catalytic activity for hydrogen evolution reaction for water splitting in alkaline electrolytes, four kinds of Ni-based alloys such as Ni, NiCo, NiCu and NiFe were prepared firstly. Based on NiCu and NiCo alloy system, nanoporous NiCu and NiCo alloys have been prepared by dealloying. The cr^^stal structure, the morphology structure and the electrochemical perfor^nance of Ni-based alloys were characterized by XRD, BET, TEM and LSV. The results show that Ni-based alloys are single-phase solid solutions with face-centered cubic cr^^stal structure and the nanoporous NiCo alloy shows homogeneously porous structure and the pore size is among of 3-6 nm. Compared with the original Ni-based alloys, the potential and Tafel slope of nanoporous NiCu and NiCo alloys reduce dramatically, while the catalytic activity enhances apparently. The low potential of nanoporous NiCo alloy is 140 mV at the current density of 20 mA/cm2 and Tafel slope is 60 mV/dec, which is close to that of Pt. Therefore, choosing synergistic doping elements and construct-ing a nanoporous structure are effective ways to enhance the catalytic activity of Ni-based alloy electrodes for hy-drogen evolution reaction.