Functionally Modified Macroporous Membrane Prepared by using Pulsed Laser Deposition

Abstract

Pulsed laser deposition (PLD) is used to deposit pure metals (Pt and Au) and a mixture of metals (Pt–Ru) at the surface of a porous aluminum anodic oxide (AAO) substrate. In the case of Pt, thick films (> 300 nm) with pore diameters larger than 150 nm (macroporous), replicating the pore structure of the underlying AAO substrate, are obtained when PLD is performed at high (> 50 eV at–1) kinetic energy (Ek) conditions. At lower Ek conditions, the characteristic structure of the AAO membrane is not discernable in the deposited film. In that case, the substrate is entirely covered by a film, the structure of which is not different from that of a Pt film deposited on a flat Si substrate under the same conditions. AAO membranes modified by macroporous Au and Pt–Ru alloy films are also prepared, demonstrating that the concept can be applied to a wide range of materials. The mechanisms responsible for the replication of the substrate pore structure in the metallic layer are discussed. These functionally modified macroporous membranes are electroactive and this aspect has been emphasized by studying the electrocatalytic properties of Pt and Pt–Ru modified macroporous membranes for CO oxidation.

Synthesis, Characterization of Nanostructured Rhodium Films and their Electrochemical Behavior towards Carbon Monoxide Oxidation

“…As the pressure in the deposition chamber is increased, the likelihood for the plasma species to lose part of their kinetic energy through a contact (collision) with the gas molecules will be also increased, thus lowering the kinetic energy of the plasma species. This variation of the kinetic energy of the plasma species induces a modification of the surface mobility of the deposited species [11]. It has been demonstrated elsewhere that the growth of Pt nanoparticles is governed by surface diffusion mechanism when PLD is performed in presence of an He background gas at pressure below 0.5 Torr [12].…”

“…Higher surface mobility of the deposited species translates into denser films and surface rearrangement that yield to minimization of the energy. This effect has been revealed to activate during the deposition of Pt, Au, and Pt-Ru films [11].…”

Binderless Nanothin Catalyst Layers for Next Generation of Micro-Fuel Cells: Concept, Fabrication, Results and Prospective

“…The effect of the background pressure on the morphology of deposits is reported in the work of Pereira et al 18 The Pt loadings as estimated by thermogravimetric analysis (TGA) were about 0.18, Prior to the electrochemical measurements in methanol, the surface of the working electrode was cleaned electrochemically by potential cycling in 0.5 M H 2 SO 4 . Before each test, dissolved oxygen was removed from the solution by bubbling argon through the solution for 20 to 30 min.…”

Soft and Hard Surface Manipulation of Nanoporous Anodic Aluminum Oxide (AAO)

“…Meanwhile, rotation of the membrane during evaporation ensured the uniformity of the resultant materials. In another approach, Pereira et al [117] reported on a simple process for the formation of a functionally modified AAO channel by using pulsed laser deposition (PLD) method to deposit a metal (i.e. Au, Pt) or a mixture of metal (i.e.…”