Ionic Polymer-Metal Composite (IPMC) actuators have been attracting a growing interest in extensive applications, which consequently raises the demands on the accuracy of its theoretical modeling. For the last few years, rough landscape of the interface between the electrode and the ionic membrane of IPMC has been well-documented as one of the key elements to ensure a satisfied performance. However, in most of the available work, the interface morphology of IPMC was simplified with structural idealization, which lead to perplexity in the physical interpretation on its interface mechanism. In this paper, the quasi-random rough interface of IPMC was described with fractal dimension and scaling parameters. And the electro-chemical field was modeled by Poisson equation and a properly simplified Nernst–Planck equation set. Then, by simulation with Finite Element Method, a comprehensive analysis on he inner mass and charge transportation in IPMC actuators with different fractal interfaces was provided, which may be further adopted to instruct the performance-oriented interface design for ionic electro-active actuators. The results also verified that rough interface can impact the electrical and mechanical response of IPMC, not only from the respect of the real surface increase, but also from mass distribution difference caused by the complexity of the micro profile.
Large scale Sb-doped ZnO nanorod arrays were grown utilizing electrochemical solution method with suitable
combination of Zn(NO3)2, HMT and SbCl3 precursors. The influences of the pH value and the substrate on the morphology and the crystallization of Sb-doped ZnO nanorods were investigated in detail. The formed Sb-doped ZnO nanorods were characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Characteristics of luminescence and crystal qualities were represented by the room temperature photoluminescence spectroscopy. It was found that the pH value had a great effect on the luminescent intensity of the ultraviolet peak and the defect-related luminescence peak. The Sb-ZnO nanorods with a hexagonal wurtzite structures fabricated under the pH value of 5 showed an intense ultraviolet emission and a weak visible emission, demonstrating the good crystal quality of the nanorods. For the substrates of flexible conductive woven nickel-copper fibers, ITO conductive glass and commercial AZO conductive glass, well-crystallized Sb-doped ZnO nanorods can be all achieved. But the crystallographic orientation of nanorods strongly relied on the substrate type.
Oxygen-ion conducting solid oxide electrolyzer (SOE) has attracted a great deal of interest because it converts
electrical energy into chemical energy directly. The oxygen evolution reaction (OER) is occurred at the anode of solid
oxide electrolyzer as the O2- being oxidized and form O2 gas, which is considered as one of the major cause of overpotentials in steam electrolyzers. This paper investigates the electrolysis of steam based on cobalt oxide impregnated La0.8Sr0.2MnO3 (LSM) composite anode in an oxide-ion-conducting solid oxide electrolyzer. The conductivity of LSM is studied versus temperature and oxygen partial pressure and correlated to the electrochemical properties of the composite electrodes in symmetric cells at 800 °C. Different contents of Co3O4 (wt.1%, 2%, 4%, 6%, 8%, 10%) were impregnated into LSM electrode and it was found that the polarization resistance (Rp) of symmetric cells gradually improved from 1.16 Ω•cm2 (LSM) to 0.24 Ω•cm2 (wt.10%Co3O4-LSM). Steam electrolysis based on LSM and wt.6%Co3O4-LSM anode electrolyzers are tested at 800°C and the AC impedance spectroscopy results indicated that the Rp of high frequency process significantly decreased from1.1 Ω•cm2 (LSM) to 0.5 Ω•cm2 (wt.6%Co3O4-LSM) under 1.8V electrolysis voltage and the Rp of low frequency process decreased from 14.9 Ω•cm2 to 5.7 Ω•cm2. Electrochemical catalyst Co3O4 can efficiently improve the electrode and enhance the performance of high temperature solid oxide electrolyzer.
Highly ordered TiO2 nanotube arrays (TNAs) were firstly fabricated by two-step anodization process. Then the Cu2O nanoparticles were deposited onto the as-fabricated TNAs via potentiostatic electrochemical deposition method in a three-electrode cell (the TNAs, Ag/AgCl and graphite performed as working electrode, reference electrode and counter
electrode, respectively). The field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and X-ray
photoelectron spectroscopy (XPS) were adopted for the morphology characterization, the crystalline phases and
composition analyzation of the as-prepared Cu2O/TNAs heterojunctions, repectively. The photoelectrochemical
performance of the Cu2O/TNAs samples was evaluated by measuring the enhanced photocurrent response under
intermittent Xe lamp irradiation. Then the photocatalytic properties were further investigated based on the photocatalytic
degradation of methyl orange (MO) solution under simulated visible light. The results indicated that the inner surface
and interface of the TNAs had been successfully modified with uniformly distributed Cu2O nanoparticles, which further ameliorated the photoelectrochemical and photocatalytic activities.
New flake-tube structured p-n heterojunction of BiOI/TiO2 nanotube arrays (TNTAs) were successfully prepared by
loading large amounts of BiOI nanoflakes onto both the outer and inner walls of well-separated TiO2 nanotubes via
anodization followed by sequential chemical bath deposition (S-CBD) method. The as-prepared BiOI/TNTAs samples
with different deposition cycles were characterized by X-ray diffraction, electron microscopy, UV-vis diffuse reflectance
spectroscopy and nitrogen sorption. The photoelectrocatalytic (PEC) activity of the BiOI/TNTAs samples toward
degradation of methyl orange (MO) solutions under visible-light irradiation were further evaluated. The visible-light PEC
activity of BiOI/TNTAs samples were further confirmed by the transient photocurrent response test. In this paper, the
5-BiOI/TNTAs sample with the best PEC activity and the highest photocurrent density among all the BiOI/TNTAs samples
was chosen as the typical delegates and emphatically discussed. The results from the current study revealed that TNTAs
consisting of well-separated nanotubes with large tube spacings were first fabricated via increasing the water proportion in
electrolyte to 10 vol. %. The synergetic effects of several factors may contribute to the remarkably enhanced PEC activities
of the 5-BiOI/TNTAs sample, including a 3D connected intertube spacing system and open tube-mouth structure, strong
visible-light absorption by BiOI, the formation of p-n heterojunction, larger specific surface area, and the impact of the
applied external electrostatic field.