Electrochemical Determination of Porosity and Surface Area of Thin Films of Interconnected Nickel Nanowires

Abstract

In this work we demonstrate electrochemical methods for determination of porosity and surface area of thin films of interconnected nickel nanowires. While the standard porosimetry and gas adsorption methods lack sensitivity for characterization of thin metallic films, the electrochemical methods employing coulometry, cyclic voltammetry and electrochemical impedance spectroscopy can be applied to accurately determine textural properties of micronand sub-micron thick nanostructured materials. Additionally, in this work we evaluated accuracy and precision of five electrochemical signals recorded during cyclic voltammetry and electrochemical impedance spectroscopy, which are commonly used for determination of electrochemical surface area (A ECSA) of various nickel electrodes. By verifying the data with two independent surface characterization techniques we found that the analysis based on surface-limited oxidation of nickel and on capacitive charging of nickel surface during hydrogen evolution reaction give the best accuracy and smallest errors. We also show that experimental conditions play a crucial role in the accurate determination of A ECSA of nickel nanomaterials. If the influence of experimental conditions is not corrected for, the electrochemical surface area can differ by over 250% compared to the surface area determined with other methods.

Metal Foam Electrode as a Cathode for Copper Electrowinning

“…Depending on the material and its porosity, one can use techniques for double electric layer estimations (cyclic voltammetry, initial charge-up dependencies, electrochemical impedance spectroscopy (EIS)), or adapt various adsorption/redox reactions that occur on the surface (underpotential depositions, adsorption measurements, reduction of various dyes, etc.) [29,[34][35][36][37][38][39]. The classical techniques for surface area estimation-liquid permeability, gas adsorption (Brunauer-Emmett-Teller technique)-in some cases can also be used [34,35,39].…”

“…[29,[34][35][36][37][38][39]. The classical techniques for surface area estimation-liquid permeability, gas adsorption (Brunauer-Emmett-Teller technique)-in some cases can also be used [34,35,39]. However, these techniques require higher amounts of materials and can have quite large error margins, depending on the geometry of the pores and the sample itself.…”

“…EIS is a very powerful and versatile in situ technique that allows not only estimating the true surface area of conducting materials but also investigating the surface and the processes happening at the surface [9,20,23,27,29]. Using the EIS technique, one can investigate both Faradaic and non-Faradaic processes on the surface simultaneously [27,29,34,35,[43][44][45][46][47]. Even the size and distribution of the pores can be characterized by employing the EIS technique [45,46].…”

Investigations into femtosecond laser hybrid manufacturing for 3D power sources

“…By increasing AEF, the percentage of "inactive" materials is reduced, resulting in a much higher total MB or MSC current obtained for similar internal current density [9]. For nanostructures or other randomly arranged 3D structures that cannot be easily measured by Brunauer-Emmett-Teller (BET) surface area analysis, increases in active surface area can be estimated by improvements in electrochemical performance instead versus a planar reference or through electrochemical surface area (ECSA) measurements [59].…”

“…Therefore, BET is not the most suitable method to determine specific surface area in this context. One of the alternatives that we are exploring for future work is on alternative methods to determine such as electrochemical surface area (ECSA) determination [59,264]. ECSA is a method where surface-limited faradic reactions are utilised to estimate the overall accessible surface area of a porous material.…”