Electric Field Effects on the Adsorption of Dopamine Species on Ag(111): DFT Investigation of Interaction Mechanism

ROSSI-FERNÁNDEZ, ANA C.; CASTELLANI, NORBERTO J.; DOMANCICH, NICOLÁS F.; MEIER, LORENA A.

ChemistrySelect

Wiley-VCH on behalf of Chemistry Europe

Lugar: Weinheim; Año: 2020 vol. 5 p. 4728 - 4739

2365-6549

The study of interactions between dopamine (DA) and noblemetal surfaces as Ag, is envisaged as a fundamental factor toattain more efficient electrochemical sensor materials. Wedescribe, in the framework of Density Functional Theory, theadsorption of four dopamine species, neutral (NDA), zwitterionic(ZDA), protonated (PDA) and deprotonated (DPDA)species on Ag(111), upon the application of an external electricfield (E), a fact of pertinence for electrochemistry tests. The ZDAand PDA species show relatively large binding energies ofabout 2.9 eV to 4.6 eV and suffer a significant flatting uponadsorption, compared with DPDA and NDA. The adsorbatesbinding energy is an increasing function of the applied E forZDA and PDA species, showing a great change when theresults for positive and negative E are compared. An electrontransfer is produced from NDA, ZDA and PDA species to Ag,while in the case of DPDA an opposite behavior is obtained. Asthe sign of E is modified, an increase of charge values in all DAspecies is observed. The theoretical results obtained here showthat ZDA and PDA species are the most affected DA speciesupon adsorption on Ag(111) and when non-zero electric fieldsare applied.