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How do gold-nanocrystal surface facets affect their electrocatalytic activities and the benzocaine-oxidation mechanism?

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Author(s):
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Rozendo, Jennifer ; Garcia, Marco A. S. ; Lima, Scarllett L. S. ; Tasic, Nikola ; Emrem, Birkan ; Fiorio, Jhonatan L. ; Solorzano, Guillermo ; Dourado, Andre H. B. ; Goncalves, Luis M. ; Paixao, Thiago R. L. C. ; Joswig, Jan-Ole ; da Silva, Anderson G. M. ; Vidinha, Pedro
Total Authors: 13
Document type: Journal article
Source: SURFACES AND INTERFACES; v. 41, p. 8-pg., 2023-08-22.
Abstract

Here we unveil the effect of gold (Au) nanocrystals with different surface facets on electrocatalytic sensing activities using benzocaine as an analyte. To this end, we performed cyclic voltammetry, differential pulse voltammetry, and in-situ Raman spectroelectrochemical experiments by employing Au nanocrystals with different exposed surface facets as electrocatalytic sensors for benzocaine. The experiments were complemented by density-functional calculations, where the rhombic dodecahedra nanocrystals, enclosed by {110} facets, showed stronger interaction energy with benzocaine, followed by cubes ({100} facets) and octahedra ({111} facets). Results from in-situ Raman spectroelectrochemical measurements have also demonstrated that the benzocaine adsorption displayed a facet-dependent behavior, which supports that the analyte can be strongly adsorbed on the Au{110} facets in comparison to {100} and {111} counterparts. In this case, we propose an oxidative mechanism of the benzocaine reaction, in which benzocaine may be electrochemically adsorbed at Au nano crystals through the -NH2 groups. After that, this -NH(Au) group is oxidized to -NO and, further to -NO2, in which different profiles were observed as a function of the Au nanocrystal facets. The effect of these facets was also observed in the oxygen reduction reaction; the rhombic dodecahedra presented a potential reduction of 200 mV, and a current increased by more than twenty times relative to the values of a commercial Au electrode (bulk). Indeed, our findings provide a deeper understanding of facet-dependent electrooxidation activity, mechanisms, and electrocatalytic detection of organic compounds. (AU)

FAPESP's process: 17/10522-5 - Development of alternative methods for fabrication of electrochemical paper-based sensors
Grantee:Thiago Regis Longo Cesar da Paixão
Support Opportunities: Regular Research Grants
FAPESP's process: 20/15230-5 - Research Centre for Greenhouse Gas Innovation - RCG2I
Grantee:Julio Romano Meneghini
Support Opportunities: Research Grants - Research Centers in Engineering Program
FAPESP's process: 19/11214-8 - Application of capillary electrophoresis for the determination of aldehydes after extraction by GDME-MIPs
Grantee:Alnilan Cristina Barros Lobato
Support Opportunities: Scholarships in Brazil - Master
FAPESP's process: 21/09630-3 - Electrocatalytic Reform of Lignin in Alkaline media: Study of Kinetics and Mechanisms for Enhanced Hydrogen Production
Grantee:André Henrique Baraldi Dourado
Support Opportunities: Scholarships in Brazil - Post-Doctoral
FAPESP's process: 18/08782-1 - Miniaturized and integrated chemical sensors: new fabrication platforms for biological, clinical and environmental applications
Grantee:Mauro Bertotti
Support Opportunities: Research Projects - Thematic Grants
FAPESP's process: 18/13922-7 - Development of a point-of-care biosensor for the swift determination of D-Dimers
Grantee:Nikola Tasic
Support Opportunities: Scholarships in Brazil - Post-Doctoral