Electrochemical nucleation and growth of aluminum nanoparticles and leaf-like flat microstructures from reline deep eutectic solvent: Effect of temperature and angular speed of working electrode

Reline低熔溶剂中铝纳米颗粒和叶状显微组织的电化学形核和长大:温度和工作电极角速度的影响

The main objective of this work was to use reline deep eutectic solvent,containing Al(III)ions,for the electrochemical study of the nucleation and growth of aluminum onto a glassy carbon electrode at different temperatures and angular speeds(ω)of the working electrode.In order to fulfill this,electrochemical and surface characterization techniques were used.It was found that as temperature increased,the onset of the Al(III)DES reduction occurred at less negative potentials while the current peak of the voltammograms increased.These indicate that Al deposition thermodynamics and kinetics were favored.Practically,no anodic current was detected due to Al passivation by Al(OH)_(3)(s)andγ-Al_(2)O_(3)(s).Atω=0 r/min,the Al deposition chronoamperograms were analyzed by a theoretical model comprising Al 3D diffusion-controlled nucleation and growth and residual water reduction.However,those recorded at different angular speeds were analyzed with a theoretical model where adsorption−desorption and diffusion-controlled nucleation−growth occurred simultaneously.The deposits were characterized by SEM,EDX,XPS and XRD.Atω=0 r/min,formation of well distributed nanoparticles((78.1±9.5)nm)was observed,while atω=900 r/min the deposit was formed by multiple 10μm diameter leaf-like flat microstructures,composed by Al,Al(OH)_(3)(s)andγ-A2O3(s).

利用电化学和表面表征技术,研究在不同温度和工作电极角速度(ω)下,含Al(III)离子的Reline低共熔溶剂中铝在玻碳电极上形核和长大的电化学行为。结果表明,随着温度的升高,Al(III)DES的还原发生在较低的负电位,而此时伏安图中的电流峰增大,这对Al沉积动力学和热力学条件有利。实际上,由于Al被Al(OH)_(3)(s)和Al_(2)O_(3)(s)钝化,未检测到阳极电流。当ω=0 r/min时,通过由Al三维扩散控制的形核、长大和残余水还原组成的理论模型,分析Al沉积时计时电流图。然而,用于分析不同角速度下的理论模型,其吸附−解吸和扩散控制的形核−长大是同时发生的。用SEM、EDX、XPS和XRD表征沉积物,结果表明,当ω=0 r/min时,形成分布良好的纳米颗粒((78.1±9.5)nm);而当ω=900 r/min时,形成直径约为10μm,由Al、Al(OH)_(3)(s)和γ-A2O3(s)组成的叶状显微组织。