The electrical double layer at the ionic liquid/Au and Pt electrode interface

• Type: Article in International Scientific Journal
• Date: 2014

Authors

Cristiana Gomes (Author) Other; Renata Costa (Author) Other; Carlos M Pereira (Author) FCUP; Fernando Silva, AF (Author) FCUP

Journal

Title: RSC Advances

Vol. 4

Pages: 28914-28921

ISSN: 2046-2069

Publisher: Royal Society of Chemistry

Indexing

ISI Web of Knowledge - 35 Citations

Scopus - 35 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-009-NB2

DOI: 10.1039/c4ra03977g

Abstract (EN): The role of the electrode material on the interfacial double layer structure of a series of ionic liquids 1-butyl-3-methylimidazolium hexafluorophosphate ([C4MIM][PF6]), 1-butyl-3-methylimidazolium bis(trifluoromethyl-sulfonyl) imide ([C4MIM][Tf2N]) and 1-butyl-3-methylimidazolium tetrafluoroborate ([C4MIM][BF4]) was investigated on gold (Au) and platinum (Pt) electrodes. The aim of this work is to contribute with experimental data to complement theoretical models that are currently under discussion in order to describe the structure of the double layer formed at the interface electrode/ionic liquid. There is still a controversy about the general shape that differential capacitance curves should present and researchers still continue making efforts to correlate the nature of the electrode/ionic liquid with the shape of the curves. Differential capacitance curves at the Au and Pt interface shows that the values of capacity follow the same order C [C4MIM][PF6] < C [C4MIM][Tf2N] < C [C4MIM][BF4]. However, the values of C are considerably lower for Pt when compared with Au for all three liquids studied. The alkyl chain length effect on the differential capacity curves was also studied at the Pt/[CnMIM][Tf2N] interface (where n = 2, 4 and 6). The results follow an expected trend except for the liquid [C6MIM][Tf2N] that shows a value of capacity near to that obtained for [C2MIM][Tf2N]. Since ionic liquids have great applicability in energy storage devices and capacitors it is of great importance to evaluate the dependence of differential capacitance as function of temperature. The results indicate that the capacity increases with increasing temperature for all systems studied in this work.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8