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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

gAu Hollow Nanoshells on Layered Graphene Oxide and Silica Submicrospheres as Plasmonic Nanozymes for Light-Enhanced Electrochemical H2O2 Sensin

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da Silva, Rafael T. P. [1] ; de Souza Rodrigues, Maria Paula [1] ; Davilla, Gabriela F. B. [1] ; da Silva, Adriano M. R. P. [1] ; Dourado, Andre H. B. [2] ; Cordoba de Torresi, I, Susana
Total Authors: 6
[1] I, Univ Sao Paulo, Dept Quim Fundamental, Inst Quim, BR-05508000 Sao Paulo - Brazil
[2] Tech Univ Munich, Dept Phys, Nonequilibrium Chem Phys, D-85748 Garching - Germany
Total Affiliations: 2
Document type: Journal article
Source: ACS APPLIED NANO MATERIALS; v. 4, n. 11, p. 12062-12072, NOV 26 2021.
Web of Science Citations: 2

Localized surface plasmon resonance (LSPR) is a phenomenon derived from the interaction between light and nanostructures, and its outcomes have been explored mainly for applications in surface-enhanced Raman spectroscopy (SERS), phototherapy, and catalysis. Bimetallic nanostructures are able to synergically combine the properties of two different metals to create a tuned response to LSPR according to their composition, shape, and morphology. In this study, an in situ synthesis of AgAu bimetallic hollow nanoshells (NS) over layered graphene oxide (GO) and silica submicrospheres (SiO2) is presented. The synthesized structures acted as peroxidase-like nanozymes in the plasmon-enhanced electrochemical sensing of H2O2. The nanozymes were submitted to 405, 533, and 650 nm laser irradiation while performing the hydrogen peroxide reduction reaction (HPRR) with a fast response speed (4 s), exhibiting enhancements in sensitivity of 122% (for Ag79Au21/GO at 533 nm, 787 mu A mM(-1) cm(-2)), 105% (for Ag79Au21/GO at 405 nm, 725 mu A mM(-1) cm(-2)) and 119% (for Ag50Au50/SiO2 at 650 nm, 885 mu A mM(-1) cm(-2)) compared to the dark conditions when matching the LSPR band maximum for each synthesized structure. When laser stimuli did not match LSPR band maximum, lower enhancements were achieved in both cases. According to Michaelis-Menten enzyme kinetics, the nanozymes I-max followed the same LSPR bias and K-m(app) was lowered after LSPR stimuli, showing the smallest values upon 405 nm irradiation (0.599 mM for Ag79Au21/GO and 0.228 mM for Ag50Au50/SiO2) demonstrating increased substrate affinity in comparison to values previously reported in enzymatic and nonenzymatic biosensors of H2O2. Thus, we propose that LSPR is the main mechanism involved in the faster electron transfer rates and the consequent enhancement of electrochemical H2O2 sensitivities, I-max, and K-m(app) by the bimetallic nanozymes synthesized by this approach. (AU)

FAPESP's process: 15/26308-7 - Optimization of the physicochemical properties of nano -structured materials for applications in molecular recognition, catalysis and energy conversion/storage
Grantee:Roberto Manuel Torresi
Support type: Research Projects - Thematic Grants
FAPESP's process: 18/16846-0 - Metal oxide nanowires decorated with gold nanoparticles for heterogeneous catalysis application
Grantee:Maria Paula de Souza Rodrigues
Support type: Scholarships in Brazil - Doctorate (Direct)
FAPESP's process: 18/16219-5 - Origin and fate of PHO-constitutive mutants in Escherichia coli
Grantee:Beny Spira
Support type: Regular Research Grants