Vibrational Stark shift spectroscopy of catalysts under the influence of electric fields at electrode–solution interfaces

Abstract

External control of chemical processes is a subject of widespread interest in chemical research, including control of electrocatalytic processes with significant promise in energy research. The electrochemical double-layer is the...

Nitrogen-doped porous carbon nanosheets as a robust catalyst for tunable CO2 electroreduction to syngas

“…Furthermore, the CO* band first appeared at −0.4 V with the consumption of dissolved CO 2 and the slight red shift of this band may be caused by the Stark tuning effect. 57 As expected, the intensity of the CO* peaks gradually increased over exposure time ranging from 0 s to 360 s (Fig. 5b), suggesting that the CO* groups were likely to be the active intermediates during the CO 2 RR process.…”

Sub-Nanometer Mapping of the Interfacial Electric Field Profile Using a Vibrational Stark Shift Ruler

“…Understanding and characterizing the nature of electric fields surrounding catalytic centers at electrode/electrolyte interfaces, or confined in molecular microenvironments, is an outstanding challenge of great current interest. The voltage applied in a typical electrochemical experiment generates an interfacial electrostatic potential that is rapidly screened by the dielectric solvent and the supporting electrolyte in the electric double layer (EDL), giving rise to large interfacial electric fields on the order of 1 V/nm at the electrode/electrolyte interface. , Surface-bound molecules feel the effect of the interfacial field and can drastically change their behavior, even to the extent of changing their chemical reactivity as influenced by the applied bias potential. ,− However, the characterization of the interfacial electric field remains challenging. Here, we introduce a spectroscopic method based on a molecular Stark shift ruler that enables mapping of the electric field strength across the electric double layer of electrode/electrolyte interfaces.…”

Nitrile Infrared Intensities Characterize Electric Fields and Hydrogen Bonding in Protic, Aprotic, and Protein Environments

“…The first vibrational Stark spectra in an external applied electric field were analyzed for simple nitriles (−CN). − Nitriles are often found in drugs, , and several methods have been developed to introduce nitrile probes at a range of positions in proteins, − nucleic acids, , and biological membrane components, as well as in nonbiological settings. − Nitrile IR transitions are relatively strong and, unlike carbonyls (−CO), occur in an uncluttered region of the IR spectrum. Unfortunately, the interpretation of nitrile frequency shifts using the language of the VSE is complicated by a well-known blueshift in H-bonding solvents, ,− undermining the utility of nitrile frequency shifts as direct quantitative probes of local electric fields, though changes in frequency can be useful at a qualitative level …”

“…We have utilized a simple phenomenological approach in this communication, motivating a more comprehensive theoretical description of TDM and frequency tuning. It may be useful to re-evaluate intensity changes seen in other studies. , Moreover, nitrile intensities can be used to determine electric fields and H-bonding in the extensive array of systems in which nitriles have been incorporated. ,− ,,,, …”