RESUMO
In this work, we present a binary composite of La(OH)3@Ni(OH)2 on carboxyl graphene (La@Ni/CG) as an electrode material. The layered La@Ni/CG double hydroxides (LDHs) were synthesized by a simple electrodeposition method in which La(OH)3 nanoparticles were first adsorbed onto carboxyl graphene and then coated with Ni(OH)2, with different particle shapes due to the large pH change near the cathodic region. Scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) were used to characterise the as-prepared La@Ni/CG composite. These results showed that the La@Ni/CG composite exhibited improved electrochemical properties, including large specific capacitance (1334.7 F g-1 at 1.4 A g-1) and capacity retention of 90.6% even after 3000 cycles, and excellent rate capability. The improved electrochemical performance of the composite can be attributed to the synergistic effect of surface adsorption and conductive pathways provided by the multiple active species (Ni, La and C) in the La@Ni/CG composite. The results presented in this work provide advances in the efficient design of nanomaterial based electrochemical energy storage devices.
RESUMO
Lanthanum-based materials have attained increasing attention because of their high adsorption property of phosphate ions and their environmental harmlessness. However, challenges still remain to improve the phosphate adsorption capacity and find suitable materials for the lanthanum attachment substrate. Nickel foam with characteristics such as excellent uniformity, large specific surface area, high porosity, and low conductivity is considered to be the alternative for the preparation of lanthanum-based adsorption materials. An efficient adsorbent foamed nickel-based La (OH)3 nanowire was first prepared with a facile one-step electrodeposition method. The batch static adsorption tests of simulative wastewater (e.g., coexisting ions and solution pH values) were employed to investigate the phosphate adsorption kinetics and solution matrix effects of the materials. The results indicate that the composite exhibits fast adsorption kinetics within 30 min and high selectivity to phosphate under interference from competing ions. The pH value of wastewater has great influence on the absorption of phosphate, and optimal adsorption capacity can be achieved over a pH 4-6 range. Various findings revealed that the adsorption behavior of lanthanum hydroxide/foamed nickel [La(OH)3/Ni] followed inner-sphere adsorption through the ligand-exchange mechanism. The prepared material is expected to be an enormous potential candidate for the removal of low-concentration phosphorus from effluents.
RESUMO
A pulse-dilation framing camera (PFC) and its working principle are introduced. The influence of the dilation pulse on the exposure time is discussed. The measurement of the dilation pulse using the PFC are theoretically analyzed and experimentally verified. The waveform and the entire time history of the potential of the dilation pulse are simulated by the known dilation factors of the PFC in theory, with the potential deviation at the end of the dilation time of pulse being approximately 3.2%. In the experiment, the exposure time and dilation factors of the PFC are measured by using an array of fiber bundles and in taking many measurements, the waveform and the entire time history of the potential of dilation pulse are achieved by the dilation factors, with the potential deviation at the end of the dilation time of pulse being approximately 6.3%. The research results show that the experimental measurement is consistent with theoretical analysis, although there are some deviations, and it is feasible to measure the waveform and the entire time history of the potential of dilation pulse using the PFC. Moreover, the research may provide an idea for new applications of the framing camera.
