Mechanism of electro-catalytic oxidation of shikimic acid on Cu electrode based on in situ FTIRS and theoretical calculations

In this paper, in situ Fourier Transform Infrared Spectroscopy (FTIRS) is used to study the electro-catalytic oxidation mechanism of shikimic acid (SA) at a copper electrode in H2O and D2O solution, respectively. As the potential is applied between 0.1 V and 0.2 V vs. SCE, SA is oxidized to 3-dehydroshikimic acid (DHS). Then a significant change appeared when the potential is scanned from 0.3 V to 0.8 V, DHS is decomposed to transaconitate and formate. As the potential is over 0.9 V, formate is further oxidized to CO2. Density functional theory (DFT) calculation of the IR spectra is in good agreement with the experimental observation. The adsorption of transaconitate through carboxyl on copper electrode is also evidenced by p- and s-polarized radiation in FTIRS.

► We studied the electro-oxidation mechanism of Shikimic acid using FTIR technique. ► The strong interference from water was eliminated. ► The intermediates in the electro-oxidation process were infered. ► The final products, i.e. transaconitate and CO2 were determined.