Suchergebnisse

The influence of glycine on the iron phosphorous alloy electrodeposition was investigated by electrochemical quartz microbalance (EQMB), in-situ external reflection FTIR spectroscopy, and electrochemical impedance spectroscopy (EIS) measurements. An increase of glycine concentration leads to a decrease of the iron-phosphorous alloy electrodeposition rate and an increase of hydrogen evolution. Strong adsorption of glycine species, such as H2(gly)þ, H(gly)± or/and Fe(gly)þ, have been observed during the hydrogen evolution and the Fe-P deposition reaction. Due to the concurrent hydrogen evolution the pH attains higher values at the interface than in the electrolyte bulk (pH2.5). The formation of adsorbed Fe(gly)þ and of the chelate complex Fe(gly)2 in solution avoids the precipitation of Fe(OH)2 in the pH range between 2.5 and ca. 7 at the interface. The phosphorous content of the iron phosphorous alloy deposit increases with the glycine concentration. This is due to a lower deposition rate of iron caused by the adsorption of Fe(gly)þ, while the hypophosphite reduction rate to phosphorous increases. ; This is a post-peer-review, pre-copyedit version of an article published in Electrochim. Acta. The final authenticated version is available online at: https://doi.org/10.1016/j.electacta.2019.03.203. This study has partially received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 778357 and from European Social Fund, project No 09.3.3-LMT-K-712-08-0003 under grant agreement with the Research Council of Lithuania.

Literaturangaben

Liquid-Assisted Pulsed Laser Ablation (LA-PLA) is a promising top-down method to directly synthesize colloidal dispersions of nanoparticles in a eco-friendly manner. However, the role of LA-PLA synthesis parameters is not yet fully agreed. This work seeks to optimize the production of nanoscale zero-valent iron (nZVI) particles suitable for biomedical or environmental applications using nanosecond LA-PLA on iron targets with different ablation media, laser and target scanning parameters. The use of alcohols as solvents produces iron-iron oxide core-shell nanoparticles with amorphous cores, except for a small crystalline fraction corresponding to the biggest core sizes. Decreasing carbon chain length and complexity leads to a thinning of the carbonaceous material coatings and an increase of the colloidal stability and the nanoparticle productivity. Moreover, a decrease of solvent density and surface tension allows obtaining reduced sizes and polydispersity values. Among, laser and scanning parameters, the pulse accumulation per spot displayed a clear effect in boosting size and productivity. As main outcome, aqueous dispersions with suitable colloidal properties are obtained, either by transferring to water of optimized nZVI particles produced in ethanol, or by direct formation of nZVI particles and in situ coating with hydrophilic molecules in aqueous solutions of these molecules ; This research has been funded by the Spanish Ministry of Economy and Competitiveness (MINECO) and FEDER [research projects MAT2015-67354R, MAT2014-53961-R, and MAT2017- 86826-R] and by the Aragón government (DGA) [grant for consolidated group PLATON E31_17R]. OBM thanks the financial support from the "Ramón y Cajal Program" [research project RYC2010-07332] of the Spanish Ministry of Economy and Competitiveness (MINECO) and the H2020 Action H2020-MSCA-IF-2014_ST [grant 656908-NIMBLIS] of the Executive Agency for Research Manages of EU Commission