Cathodic Deposition of Triangular Tungsten Clusters from Ionic Liquids: An Explorative Study

In the present work, the triangular tungsten clusters {[W3O2(O2CCH3)6](H2O)3}(CF3SO3)2 and {[W3O2(O2CCH2CH3)6](H2O)3}(BF4)2. 5.5H2O were dissolved in both hydrophobic and hydrophilic ionic liquids (ILs) and subjected to a cathodic potential of roughly 2V. It was proposed that successful deposition of these metal clusters on a platinum electrode would yield Pt-supported anodic catalysts which could be used in ethanol fuel cells (EFCs). Visual examination of the electrode surfaces indicated that a film had been deposited, however, the surface with W3(CF3SO3)2 quickly oxidized when removed from the IL. Therefore, SEM imaging and EDX analysis of the W3(BF4)2 surface were performed. The data indicated that the film was composed mainly of carbon, oxygen, nitrogen, iron and fluorine with very little tungsten contribution. Electronic spectra taken pre- and post-deposition suggest that structural changes to the W3O2 unit occurred with the disintegration of the triangular geometry being a thermodynamically favored route