A Direct Catalytic Ethanol Fuel Cell (DCEFC) Modified by LDHs, or by Catalase-LDHs, and Improvement in Its Kinetic Performance: Applications for Human Saliva and Disinfectant Products for COVID-19

Abstract

In this work, it has been experimentally proven that the kinetic performance of a common Direct Catalytic Ethanol Fuel Cell (DCEFC) can be increased by introducing nanostructured (ZnII,AlIII(OH)2)+NO3−·H2O Layered Double Hydroxides (LDHs) into the anode compartment. Carrying out the measurements with the open-circuit voltage method and using a kinetic format, it has been shown that the introduction of LDHs in the anodic compartment implies a 1.3-fold increase in the calibration sensitivity of the method. This improvement becomes even greater in the presence of hydrogen peroxide in a solution. Furthermore, we show that the calibration sensitivity increased by 8-times, when the fuel cell is modified by the enzyme catalase, crosslinked on LDHs and in the presence of hydrogen peroxide. The fuel cell, thus modified (with or without enzyme), has been used for analytical applications on real samples, such as biological (human saliva) and hand disinfectant samples, commonly used for the prevention of COVID-19, obtaining very positive results from both analytical and kinetic points of view on ethanol detection. Moreover, if the increase in the calibration sensitivity is of great importance from the point of view of analytical applications, it must be remarked that the increase in the speed of the ethanol oxidation process in the fuel cell can also be extremely useful for the purposes of improving the energy performance of a DCEFC.

Improvement of Qualitative Analyses of Aliphatic Alcohols Using Direct Catalytic Fuel Cell and Chemometric Analysis Format

“…In fact, in this case, as has been said, the method involves recording not only each of the discharge curves, but also each of the charge curves, of each of the individual alcohols. These charge latter curves, although seeming to contain more information than the discharge ones, take a rather long time to be recorded (about an hour, or even more), since it is well known that the total oxidative process proceeds through various steps with set periods [2,3,[19][20][21][22][23], which create a significant increase in total analysis times. Although the results of this method were undoubtedly accurate, a certain inconvenience manifested itself in the inevitable lengthening of time of the total process of the analysis.…”

“…Finally, despite this paper having shown that DCMFC results, once analyzed using a chemometrics data treatment, are a valid and simple alternative format for the detection and identification of organic molecules characterized by at least one alcohol group, a likely further improvement of this format will be made possible by the integration, into the anodic compartment of the DCMFC device, of nanostructured materials, such as Layered Double Hydroxides (LDHs), also known as hydrotalcite-like compounds (or even enzymes such as catalase) [23].…”