Metallic nanoparticles growth on ionic layer grafted onto glassy carbon for hydrogen evolution reaction

• Published in: Journal of molecular liquids 2021-11, Vol.341, p.117433, Article 117433
• Main Authors: Bencherif, Selma, Mechouet, Mourad, Ghilane, Jalal
• Format: Article
• Language: English
• Subjects: Chemical Sciences; Electrocatalysis; hydrogen evolution reaction (HER); Ionic organic layer; Material chemistry; Scanning electrochemical microscope; Surface modification
• ISSN: 0167-7322
• DOI: 10.1016/j.molliq.2021.117433

[Display omitted] •Electrochemically grafting of ionic layer based ionic liquid.•Electrochemical growth of metallic nanoparticles onto ionic layer.•Local electrochemical reactivity of ionic layer.•Ionic layer/ metallic nanoparticles as electrocatalyst for hydrogen evolution reaction. The present work reports the immobilization of thin ionic layer onto glassy carbon and its use as a platform for the electrochemical growth of metallic nanoparticles. The ionic layer was electrochemically grafted during the reduction of the in situ generated diazonium bearing imidazolium, 1-nitrophenylethyl 3-methylimidazolium bis(trifluoromethyl- sulfonyl)imide. Next, the metallic nanoparticles, platinum or palladium, were electrochemically grown onto the ionic layer modified electrodes. The physico-chemical properties of the generated modified electrodes were studied by surfaces analysis and electrochemical methods. Furthermore, the electron transfer properties of the modified electrodes were investigated at the local scale using scanning electrochemical microscope (SECM). The obtained results confirm the success of the ionic layer grafting as well as the formation of the metallic nanoparticles. The SECM investigations display change in the electron transfer properties of the modified electrodes depending on the used redox mediator. Finally, the as-prepared modified electrodes catalytic performances of towards the hydrogen evolution reaction (HER) were evaluated. Interestingly, the presence of the ionic layer displays an increase of the catalytic performances, for both investigated metallic nanoparticles. This behavior is probably due to the existence of synergistic effect between the grafted ionic layer and the metallic nanoparticles. Therefore, it is anticipated that the ionic layer immobilization had several features including the tuning of the electrode interface properties, acting as a platform and binder for the nanoparticles growth as well as the enhancement of the electrocatalytic performances.