Structure Investigation and Electrochemical Behavior of γ-MnO2 Synthesized from Three-Dimensional Framework and Layered Structures

The frequent occurrence of furazolidone (FZD) in environmental fluids reveals the ongoing increase in use and raises concerns about the need of monitoring it. To investigate the electrochemical behavior of FZD, a novel sensor of manganese molybdenum oxide (MMO) micro rods adorned three-dimensional porous carbon (PC) electrocatalyst was constructed. The crystalline structure and surface morphology of the MMO/PC composite was characterized by XRD, Raman, FESEM, and HR-TEM. Electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and amperometric(i-t) methods were used to assess the electrocatalytic activity of modified electrodes. In the presence of FZD, the as-fabricated MMO/PC modified glassy carbon electrode (GCE) performed better at lower potentials with a greater peak current than other modified GCE. These results emanate from the synergistic effect of the MMO/PC suspension on the GCE. The electrochemical behavior of the amperometric(i-t) technique was used to determine FZD. Amperometric(i-t) detection yielded linear dynamic ranges of 150 nM to 41.05 µM and 41.05 to 471.05 µM with detection limits of 30 nM. The MMO/PC hybrid sensor was also effectively used to detect FZD in environmental fluids, yielding ultra-trace level detection.

Download Full-text

Transient and steady-state temperature rise in three-dimensional anisotropic layered structures in pump-probe thermoreflectance experiments

Journal of Physics D Applied Physics ◽

10.1088/1361-6463/abbd64 ◽

2020 ◽

Vol 54 (3) ◽

pp. 035304

Author(s):

Puqing Jiang ◽

Heng Ban

Keyword(s):

Steady State ◽

Temperature Rise ◽

Three Dimensional ◽

Layered Structures ◽

Pump Probe ◽

Steady State Temperature ◽

Transient And Steady State

Download Full-text

Structural insights intoM2O–Al2O3–WO3(M= Na, K) system by electron diffraction tomography

Acta Crystallographica Section B Structural Science Crystal Engineering and Materials ◽

10.1107/s2052520615007994 ◽

2015 ◽

Vol 71 (3) ◽

pp. 349-357 ◽

Cited By ~ 6

Author(s):

Iryna Andrusenko ◽

Yaşar Krysiak ◽

Enrico Mugnaioli ◽

Tatiana E. Gorelik ◽

Diana Nihtianova ◽

...

Keyword(s):

Electron Diffraction ◽

Three Dimensional ◽

Large Cell ◽

Systematic Investigation ◽

Electron Diffraction Data ◽

Diffraction Tomography ◽

Structure Investigation ◽

X Ray ◽

Cell Parameters ◽

Wide Range

TheM2O–Al2O3–WO3(M= alkaline metals) system has attracted the attention of the scientific community because some of its members showed potential applications as single crystalline media for tunable solid-state lasers. These materials behave as promising laser host materials due to their high and continuous transparency in the wide range of the near-IR region. A systematic investigation of these phases is nonetheless hampered because it is impossible to produce large crystals and only in a few cases a pure synthetic product can be achieved. Despite substantial advances in X-ray powder diffraction methods, structure investigation on nanoscale is still challenging, especially when the sample is polycrystalline and the structures are affected by pseudo-symmetry. Electron diffraction has the advantage of collecting data from single nanoscopic crystals, but it is frequently limited by incompleteness and dynamical effects. Automated diffraction tomography (ADT) recently emerged as an alternative approach able to collect more complete three-dimensional electron diffraction data and at the same time to significantly reduce dynamical scattering. ADT data have been shown to be suitable forabinitiostructure solution of phases with large cell parameters, and for detecting pseudo-symmetry that was undetected in X-ray powder data. In this work we present the structure investigation of two hitherto undetermined compounds, K5Al(W3O11)2and NaAl(WO4)2, by a combination of electron diffraction tomography and precession electron diffraction. We also stress how electron diffraction tomography can be used to obtain direct information about symmetry and pseudo-symmetry for nanocrystalline phases, even when available only in polyphasic mixtures.

Download Full-text