摘要
采用快速凝固与脱合金化相结合的方法制备纳米多孔Ni,经热处理氧化获得纳米多孔NiO,运用XRD、SEM、TEM、BET等对纳米多孔Ni、NiO的物相、形貌结构、孔径分布进行表征,并通过循环伏安、稳态极化、电化学阻抗法研究了其作为电极的电催化析氧性能。结果表明,Ni 15 Al 85和Ni 5Al 95脱合金化后均获得了纳米多孔Ni,Al含量的增加使得Ni的孔径尺寸与骨架强度减小,Ni 5Al 95形成的纳米多孔Ni在10 mA·cm^-2电流密度下的析氧过电位比Ni 15 Al 85形成的纳米多孔Ni低95 mV,但随着反应的进行,纳米多孔Ni表面的孔洞开始坍塌和脱落,导致其析氧稳定性降低。NiO继承了Ni的纳米多孔结构,比表面积和骨架强度进一步增大,Ni 5Al 95合金获得的纳米多孔NiO在10 mA·cm^-2电流密度下的析氧过电位仅为357 mV,相比Ni电极降低了14.3 mV,室温下析氧反应的表观交换电流密度是Ni电极的1.2倍,表观活化自由能降低了8.59 kJ·mol^-1,经1 000圈循环伏安后过电位降低了12 mV(J=100 mA·cm^-2),具有优良的电催化析氧性能和良好的稳定性。
Nanoporous Ni was prepared by a combined method of rapid quenching and de-alloying, and then prepared samples were heated to synthesize the nanoporous NiO. The phase, morphology, microstructure and pore-size distribution of nanoporous Ni and NiO were analyzed by XRD, SEM, TEM, BET respectively.The electrochemical performance was investigated by cyclic voltammetry, electrochemical steady-state polarization and electrochemical impendence spectroscopy (EIS). The results showed that nanoporous Ni could be obtained after de-alloying of Ni 15 Al 85 and Ni 5Al 95 alloy. The bore diameter and skeleton strength of Ni decreased as the Al content increased. Under the current density of 10 mA·cm^-2 , oxygen evolution reaction overpotential of nanoporous Ni drove from Ni 5Al 95 alloy was 95 mV lower than nanoporous Ni from Ni 15 Al 85 alloy. However, with the reaction proceeded, collapse and detachment of the surface holes reduced the stability of oxygen evolution. NiO inherited the nanoporous structure of Ni, and further increased the specific surface area and skeleton strength of the electrode. Under the current density of 10 mA·cm^-2 , oxygen evolution reaction overpotential of nanoporous NiO electrode was only 357 mV, which lower than Ni electrode 14.3 mV. The apparent exchange current density of NiO electrode toward the OER was 1.2 times as high as that of nickel electrode in room temperature, the apparent activation energy reduced 8.59 kJ·mol^-1 , after 1 000 cycles, overpotential of NiO minished 12 mV ( J =100 mA·cm^-2 ), nanoporous NiO drove from Ni 5Al 95 alloy had superior electrocatalytic properties toward the oxygen evolution reaction and favorable stability.
作者
周琦
任向荣
ZHOU Qi;REN Xiangrong(State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals, Lanzhou University of Technology, Lanzhou 730050)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2019年第22期3701-3707,共7页
Materials Reports
基金
国家自然科学基金(51661018)~~
关键词
快速凝固
脱合金化
纳米多孔镍
析氧性能
阳极材料
电解水
rapid quenching
de-alloying
nanoporous Ni
oxygen evolution reaction
anode material
electrolysis of water
