Analysis and characterization of materials with multiresponse techniques based on electrochemistry
Multiresponse techniques allow us to obtain simultaneously very different but complementary information about a chemical system while it evolves with time. For example, spectroelectrochemistry supplies spectrophotometric and electrochemical information during the oxidation and/or reduction of a chemical. Depending on the spectroscopic technique selected (UV-Vis absorption, NIR absorption, Raman scattering, etc.) and the electrochemical technique used different aspects of the system studied can be registered. Other kind of analytical techniques can be also coupled to obtain simultaneously information related to mass changes, electrical conductivity changes, etc.
These multiresponse analytical techniques allow us to study very different chemical systems and processes under very different experimental conditions. Some of them are electrosynthesis and characterization of conducting polymers, electrogeneration and characterization of metal nanoparticles, study of different nanostructures such as carbon nanotubes, graphene or nanoparticles, spectroelectrochemical determination of different biochemical compounds, characterization of different inorganic compounds, etc
Our research group designs, constructs, and develops our own devices to perform these kinds of studies because they have not been commercialized yet. Therefore we are able to better adapt our technology to the system we are analyzing, depending on its specific properties, its reactivity, its stability, etc. This versatility has allowed us to analyzed very different systems: inorganic species, organic compounds, biochemical systems, nanostructured materials, conducting polymers, etc
Multiresponse techniques are based on the simultaneous registration of different signals related to a chemical system, usually while it evolves during a chemical reaction. The most developed multiresponse techniques in our group are those related to spectroelectrochemistry, but other possible couplings are possible, always depending on the chemical system studied.
Thus, UV-Visible spectroelectrochemistry registered simultaneously information related to the temporal evolution of the UV-Visible spectra of a system during its oxidation and/or reduction. Different arrangements are possible depending on the direction the electromagnetic light beam goes through the solution studied. On the other hand, Raman spectroelectrochemistry supplies information about changes in Raman spectra during an electrochemical reaction taking place in the spectroelectrochemical cell.
Other possibilities such as Spectroeletrochemical Quartz Crystal Microbalance, Potentiometric spectroelectrochemistry, Spectroelectrochemistry coupled with Electrochemical Impedance Spectroscopy are also possible.
Our techniques and all the elements necessary to perform this kind of analysis are not commercialized yet. This can suppose a disadvantage but not real because our group is able to adapt all the instrumental devices to the needs of each system and chemical problem. There are many possibilities of coupling the instruments and the spectroelectrochemical cells can be designed and constructed depending on the chemical system.
Every system susceptible to be reduced and/or oxidized, that shows changes in its spectral feature during this process, can be studied with spectroelectrochemical techniques. Thus different chemical systems and materials are studied during its synthesis determining its mechanism of reaction, are characterized obtaining very valuable information about all changes occurs, etc. Some of these chemical systems studied are conducting polymers, metal nanoparticles, carbon nanomaterials such as carbon nanotubes of grapheme, inorganic complexes, biomolecules, etc.Other application field in which spectroelectrochemistry is useful is in quantitative analysis because usually the two signals are proportional to concentration. Thus, the measurements performed are autovalidated being not necessary the comparison of the results with other analytical technique.
Some of the spectroelectrochemical devices developed in our group have been registered in the Spanish Patent Agent.
Jose Manuel López López
+34 947 25 8895