INFIQC   05475
INSTITUTO DE INVESTIGACIONES EN FISICO- QUIMICA DE CORDOBA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
PHOSPHATE ADSORPTION ON Ag (111): A DFT STUDY
Autor/es:
CLAUDIA BEATRIZ SALIM ROSALES; MARIANA ISABEL ROJAS; LUCÍA BERNARDITA AVALLE
Lugar:
Córdoba
Reunión:
Workshop; Quantum Espresso Spring School; 2015
Institución organizadora:
Facultad de Ciencias Químicas, Univ. Nac. de Córdoba
Resumen:
Recentry, by means of electrochemicaland nonlinear optical techniques, it was studied the adsorption of riboflavin(RF) and flavin mononucleotide (FMN) on Ag(111) surfaces, having orderedstructures of C3V symmetry. In the case of RF films, the L-cysteinedisplaces the RF adsorbed molecules [1]. The studyof these systems is of technological interest, due to the application onbiomedical devices and biosensors, being important to know, for differentenvironments, how these biomolecules interact with the electrode surface andthus determine its stability and functionality.FMN has a phosphate group in the terminal chain, which is probably theanchor group to the Ag(111) surface, and the responsible of the differences observedin cyclic voltammetry (CV) measurements realized in KClO4 0.010 Msolution. [1] As to inspect this hypothesis, in thisstudy the adsorption of phosphate species on Ag (111) is experimentally andtheoretically studied.H2PO4- experimental injections werecarried out in the electrochemical cell recording the current signal versustime to reach steady state. For the different concentrations of phosphate(between 6.67x10-7 M and 1x10-5M) the CV andelectrochemical impedance spectroscopy (EIS) were obtained.In the present work, by means of quantum mechanical calculations with the SIESTAcode [2], H2PO4- andHPO4-2 adsorption was investigated. For each of theadsorbates we consider different possible adsorption sites, the surface chargeand the partial density of states at different coverages, assuming theformation of ordered structures.The results obtained from computer calculations and experimentalmeasurements gave a good correlation.