Electrocatalytic Behavior of Pd and Pt Nanoislands Deposited onto 4,4′-Dithiodipyridine SAMs on Au(111)
- 106 Downloads
Using different electrochemical techniques as well as in situ scanning tunneling microscopy (STM) and ultraviolet photoelectron spectroscopy (UPS), we investigated the electrocatalytic oxidation of carbon monoxide and methanol on palladium and on platinum nanoislands, which were deposited onto 4,4′-dithiodipyridine self-assembled monolayers (SAMs) on Au(111) single crystal electrodes. Electrochemical and morphological measurements performed on these monoatomic high metal deposits on top of the SAM show rather different island growth along with variations in metal coverage and particle size. UPS He-II valence band spectra of all Pt deposits reveal no intensity at the Fermi energy, so that the resulting nanoislands can be considered as non-metallic. While the electronic and structural properties do not affect carbon monoxide adsorption, the metal coverage has a tremendous impact on the catalytic activity regarding CO oxidation as well as methanol oxidation.
KeywordsElectrocatalysis Self-assembled monolayers Metallization CO oxidation Methanol oxidation
The authors thank Claus Müller for his technical STM support.
Financial support has been received from the Deutsche Forschungsgemeinschaft (DFG) through the grant KO 576/28-1.
- 5.C. Vericat, M.E. Vela, G. Benitez, P. Carro, R.C. Salvarezza, Self-assembled monolayers of thiols and dithiols on gold: new challenges for a well-known system. Chem. Soc. Rev. 39(5), 1805–1834 (2010)Google Scholar
- 13.G. Cuniberti, G. Fagas, and K. Richter, in Introd. Mol. Electron. (Lecture Note Physics), edited by G. Cuniberti, K. Richter, G. Fagas (Springer Berlin, Berlin, 2005), pp. 1–10Google Scholar
- 17.E.A. Speets, P. Te Riele, M.A.F. Van Den Boogaart, L.M. Doeswijk, B.J. Ravoo, G. Rijnders, J. Brugger, D.N. Reinhoudt, D.H.A. Blank, Formation of metal nano- and micropatterns on self-assembled monolayers by pulsed laser deposition through nanostencils and electroless deposition. Adv. Funct. Mater. 16(10), 1337–1342 (2006)CrossRefGoogle Scholar
- 20.I. Thom, G. Hähner, M. Buck, Replicative generation of metal microstructures by template-directed electrometallization. Appl. Phys. Lett. 87(2), 024101 1–3 (2005)Google Scholar
- 29.F. Eberle, M. Saitner, H.-G. Boyen, J. Kucera, A. Gross, A. Romanyuk, P. Oelhafen, M. D’Olieslaeger, M. Manolova, D.M. Kolb, A molecular double decker: extending the limits of current metal-molecule hybrid structures. Angew. Chemie - Int. Ed 49(2), 341–345 (2010)Google Scholar