Advancing H2O2 electrosynthesis: tuning electronic interactions for efficient two-electron oxygen reduction on controlled AgAu nanostructures

Oliveira Muller, Matheus, dos Santos Pereira, Fellipe, Anchieta e Silva, Felipe, Morgan, David J. ORCID: https://orcid.org/0000-0002-6571-5731, Tofanello, Aryane, Azevedo Silva, Augusto César, Rodrigues, Thenner Silva, D’Elia, Eliane and Suller Garcia, Marco Aurélio 2026. Advancing H2O2 electrosynthesis: tuning electronic interactions for efficient two-electron oxygen reduction on controlled AgAu nanostructures. Applied Surface Science 736 , 166819. 10.1016/j.apsusc.2026.166819

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Abstract

The selective two-electron oxygen reduction reaction (ORR) to H2O2 represents an attractive alternative to energy-intensive anthraquinone-based processes, yet its efficiency critically depends on precise control of the catalyst’s electronic structure. Herein, we investigate AgxAuy bimetallic nanostructures, prepared via a galvanic replacement strategy and supported on SiO2, as model systems to elucidate how compositional tuning and nanostructural evolution govern ORR activity and selectivity. Electrochemical measurements revealed that ORR performance does not scale linearly with Au content; instead, catalysts with intermediate Ag/Au ratios exhibit superior H2O2 selectivity and Faradaic efficiency, along with favorable onset potentials, while maintaining metallic characteristics across the set. Interestingly, electron paramagnetic resonance (EPR) spectroscopy provided an electronic descriptor: excessive Au incorporation generates strong EPR signals and spectral broadening, indicative of electronic over-perturbation and increased heterogeneity, which correlates with ORR onset behavior. Microscopy analyses further show that Au-rich samples undergo over-etching and structural collapse, imposing physical limits on electronic optimization. Additionally, theoretical calculations corroborate these findings, indicating that intermediate AgxAuy compositions possess favorable d-band centers and metal-support interactions. Overall, this study demonstrates that efficient and selective H2O2 electrosynthesis arises from a narrow compositional window in which Au electronically tunes Ag-derived active ensembles.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Schools > Chemistry
Publisher:	Elsevier
ISSN:	0169-4332
Date of First Compliant Deposit:	20 April 2026
Date of Acceptance:	4 April 2026
Last Modified:	07 Aug 2026 22:17
URI:	https://orca.cardiff.ac.uk/id/eprint/186503

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