title: 3D-nanoarchitectured Pd/Ni catalysts prepared by atomic layer deposition for the electrooxidation of formic acid.
abstract: Three-dimensionally (3D) nanoarchitectured palladium/nickel (Pd/Ni) catalysts, which were prepared by atomic layer deposition (ALD) on high-aspect-ratio nanoporous alumina templates are investigated with regard to the electrooxidation of formic acid in an acidic medium (0.5 M H2SO4). Both deposition processes, Ni and Pd, with various mass content ratios have been continuously monitored by using a quartz crystal microbalance. The morphology of the Pd/Ni systems has been studied by electron microscopy and shows a homogeneous deposition of granularly structured Pd onto the Ni substrate. X-ray diffraction analysis performed on Ni and NiO substrates revealed an amorphous structure, while the Pd coating crystallized into a fcc lattice with a preferential orientation along the [220]-direction. Surface chemistry analysis by X-ray photoelectron spectroscopy showed both metallic and oxide contributions for the Ni and Pd deposits. Cyclic voltammetry of the Pd/Ni nanocatalysts revealed that the electrooxidation of HCOOH proceeds through the direct dehydrogenation mechanism with the formation of active intermediates. High catalytic activities are measured for low masses of Pd coatings that were generated by a low number of ALD cycles, probably because of the cluster size effect, electronic interactions between Pd and Ni, or diffusion effects.
authors.affiliation: Aix-Marseille Université, CNRS, CINaM UMR 7325, 13288, Marseille, France.
authors.forename: Loïc
authors.initials: L
authors.lastname: Assaud
authors.affiliation: Department of Chemical and Biological Engineering, Center for Catalysis Research and Innovation, University of Ottawa, 161 Louis-Pasteur St., Ottawa, ON, K1N 6N5, Canada.
authors.forename: Evans
authors.initials: E
authors.lastname: Monyoncho
authors.affiliation: Aix-Marseille Université, CNRS, CINaM UMR 7325, 13288, Marseille, France.
authors.forename: Kristina
authors.initials: K
authors.lastname: Pitzschel
authors.affiliation: Department of Chemical and Biological Engineering, Center for Catalysis Research and Innovation, University of Ottawa, 161 Louis-Pasteur St., Ottawa, ON, K1N 6N5, Canada.
authors.forename: Anis
authors.initials: A
authors.lastname: Allagui
authors.affiliation: Aix-Marseille Université, CNRS, CINaM UMR 7325, 13288, Marseille, France.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Petit
authors.affiliation: Aix-Marseille Université, CNRS, CINaM UMR 7325, 13288, Marseille, France.
authors.forename: Margrit
authors.initials: M
authors.lastname: Hanbücken
authors.affiliation: Department of Chemical and Biological Engineering, Center for Catalysis Research and Innovation, University of Ottawa, 161 Louis-Pasteur St., Ottawa, ON, K1N 6N5, Canada.
authors.forename: Elena A
authors.initials: EA
authors.lastname: Baranova
authors.affiliation: Aix-Marseille Université, CNRS, CINaM UMR 7325, 13288, Marseille, France.
authors.forename: Lionel
authors.initials: L
authors.lastname: Santinacci
keywords: Pd/Ni; anodic aluminum oxide; atomic layer deposition (ALD); direct formic acid fuel cells; electrooxidation; nanostructured catalysts