The order of addition and time matters: Impact of electrolyte processing on micelle-assisted electrosynthesis of mesoporous alloys
- Journal Article
Mesoporous thin films are currently awaking a considerable interest for their prospective use in applications ranging from catalysis to energy storage. Yet, some of the synthetic parameters enabling a reproducible development of mesoporosity remain uncontrolled. In this research, we demonstrate that a subtle change in the procedure for the electrolyte preparation for the electrosynthesis of mesoporous Co‒Pt films is critical for reproducing the mesoporosity of the alloys. Specifically, we show that dissolution of the platinum salt (Na2PtCl6·6H2O) in water and storage of the solution (referred to as ‘equilibration time’) before adding the remaining reagents and additives (CoCl2 and P-123) are imperative to consistently reproduce the films mesoporosity. Highly mesoporous Pt-rich Co‒Pt films (10–23 at.% Co), with a pore diameter of 10‒17 nm, were obtained from an electrolyte that involved an equilibration time, while mesoporosity was often absent in films grown from a freshly prepared electrolyte (i.e., upon dissolving all chemicals immediately before electrodeposition). The results suggest that pore formation is governed by the complexation dynamics of Pt(IV) in water, which was investigated by UV–vis spectroscopy. Namely, the concentration of hydroxochloroplatinate complexes ([PtCl6-x(OH)x]2–) originating from the exchange of Cl– by OH– ions increase during the equilibration time. [PtCl6-x(OH)x]2– species would interact more favorably with the hydrophilic poly(ethylene oxide) moieities of P-123 micelles than [PtCl6]2–. The distinct interaction between micelles and the complexes of platinum is key for the reproducible generation of a mesoporous network. Our finding highlights the relevant role of electrolyte processing for the control of mesoporosity in metallic systems prepared by micelle-assisted electrodeposition, which we believe can be extended to many electrolytic processes. © 2020 Elsevier Ltd Show more
Journal / seriesElectrochimica Acta
Pages / Article No.
SubjectElectrolyte processing; Electrodeposition; Mesoporous alloys; Cobalt-platinum; Amphiphilic surfactant
Organisational unit08705 - Gruppe Pané Vidal
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