Mott–Schottky analysis of flower‐like ZnO microstructures with constant phase element behavior

Abstract

ZnO was prepared using room temperature bipolar electrochemical process in deionized water. Electron microscopy, powder X‐ray diffraction, and micro‐Raman spectroscopy showed crystallization of the material into the wurtzite hexagonal structure of ZnO, self‐organized in micro‐sized flower‐like shapes that are formed out of individual nanorods preferentially grown along the <0thinmathspace0thinmathspace0thinmathspace1> direction. The intrinsic electronic properties were evaluated by potentiodynamic electrochemical impedance spectroscopy using Mott–Schottky analysis of semiconductor/liquid junctions. Because the flat band and carrier density are frequency‐dependent, we used an approximation based on fractional order capacitance fitting, and subsequently three different ways to calculate the frequency‐independent effective capacitance of the system. The capacitance computed using the four parameters of single‐dispersion Randle's model, i.e., pseudocapacitance, dispersion coefficient, and series and parallel resistances, is more recommended for the characterization of the electrochemical system.

Earth‐Abundant Tin Sulfide‐Based Photocathodes for Solar Hydrogen Production

“…The Mott-Schottky plots exhibited frequency dispersion indicating surface states, a trend observed in most nanostructured films. [30][31][32] The donor concentration of the films (measured from the slope of the 1/C 2 vs E plots) ranged from 3.6 × 10 17 cm −3 (at 18.2 kHz) to 1.57 × 10 19 cm −3 (at 1.1 kHz), based on a relative dielectric constant of 19.5. [33] The flat-band potential (E fb ) obtained from the x-intercept of the 1/C 2 versus E plots, showed narrow ranges from 0.17 V versus RHE (at 1.1 kHz) to 0.20 V versus RHE at (18.2 kHz).…”

High photoresponse and fast carrier mobility: Two‐dimensional rGO‐AgBr/Ag composite based on Z‐scheme heterointerface with plasma for hydrogen evolution

“…Obviously, the smallest Tafel slope and η of rGAA-2 reflect the high-efficient catalytic hydrogen production, [79][80][81] which is matched with the HER results. 82,83 Based on aforementioned research, the VLD catalytic mechanism of rGAA-α catalyst was confirmed to be the model as Figure 9. Generally, in M-S plots, the positive and negative slope of the linear region represent the electron donor characteristic and electron acceptor characteristic.…”

“…However, both the electron donor effect and electron receptor effect can be found in rGAA-2 composite for the obvious positive and negative slope in its M-S plots ( Figure 8E), suggesting that the effective electron transfer system (heterointerface) was constructed between AgBr and rGO, so that the electrons can easily transfer to the AgBr catalyst from rGO structure. 82,83 Based on aforementioned research, the VLD catalytic mechanism of rGAA-α catalyst was confirmed to be the model as Figure 9. The VB potential of rGO is confirmed as 2.13 eV by XPS VBs analysis, and it is well known that the HOMO of rGO is very close to its LUMO, 84,85 so that its π→π* transition can easily be induced by visible-light.…”

Antimicrobial Peptide Functionalized Conductive Nanowire Array Electrode as a Promising Candidate for Bacterial Environment Application

“…The dielectric and insulating properties at the electrode/electrolyte interface can be indicated by R ct and Q . On the other hand, the heterogeneity of the electrode/solution interface is related to Q . The change in redox on the surface of the electrode can be manifested by a change in R ct .…”