Disposable Copper Electrodes Based on Printed Circuit Board Technology for the <i>Operando</i> Generation of Raman-Enhancing Substrates

Most surface-enhanced Raman scattering (SERS) substrates reported in the literature consist of plasmonic nanostructures, mainly based on gold or silver. Although Cu plasmonic properties have been known for decades, Cu-SERS substrates remain limited by their limited chemical stability. Nevertheless, many researchers claim that Cu-based SERS substrates should be revisited, as new synthetic strategies have led to the improved stability of Cu nanostructures. Among these, the electrosynthesis of Cu nanomaterials has been proposed as an interesting approach because it allows the in situ generation of SERS substrates. Additionally, the combination of electrochemistry with <i>operando</i> Raman spectroscopy, also known as Raman spectroelectrochemistry, provides real-time information about the electrogenerated SERS substrates. In this work, we report the use of Cu-printed circuit boards to create an electrochemical platform, which can be used for the <i>operando</i> generation of Cu-based SERS substrates in chloride media. These SERS substrates exhibit great potential for the detection of tertiary amines such as cocaine, fentanyl, paraquat, or adenine. A complementary study using bidimensional UV/vis absorption spectroelectrochemistry was carried out to fully understand the processes occurring during the <i>operando</i> generation of the Cu-SERS substrates.