37 results about "Underpotential deposition" patented technology

High-surface-area carbon nanostructures coated with a smooth and conformal submonolayer-to-multilayer thin metal films and their method of manufacture are described. The preferred manufacturing process involves the initial oxidation of the carbon nanostructures followed by immersion in a solution with the desired pH to create negative surface dipoles. The nanostructures are subsequently immersed in an alkaline solution containing non-noble metal ions which adsorb at surface reaction sites. The metal ions are then reduced via chemical or electrical means and the nanostructures are exposed to a solution containing a salt of one or more noble metals which replace adsorbed non-noble surface metal atoms by galvanic displacement. Subsequent film growth may be performed via the initial quasi-underpotential deposition of a non-noble metal followed by immersion in a solution comprising a more noble metal. The resulting coated nanostructures may be used, for example, as high-performance electrodes in supercapacitors, batteries, or other electric storage devices.

The invention discloses a nanoporous gold supported ultrathin platinum metal film catalyst; the catalyst is an alloy sheet which is 0.1 - 100 micrometer thick, 0.1 - 10cm wide, and 0.1 - 20cm long, and is uniformly covered with a platinum metal atom layer on the surface thereof; the invention takes the method of under-potential depositing copper, silver or lead on the nanoporous gold and then performing exchange with the platinum metal cations to deposit the platinum metal film on the surface of the porous gold, thus obtaining the nanoporous gold supported ultrathin platinum metal film catalyst. The catalyst material prepared by the method of the invention can be easily controlled with regards to the aperture size, pore wall thickness and the platinum metal film thickness; and the catalyst is characterized by high specific surface area, high utilization ratio of the platinum metal, good catalytic activity and high anti-poisoning property.

A method is provided, including the following operations: depositing a liner in a feature of a substrate; depositing a monolayer of zinc over the liner; after depositing the monolayer of zinc, performing a thermal treatment on the substrate, wherein the thermal treatment is configured to cause migration of the zinc to an interface of the liner and an oxide layer of the substrate, the migration of the zinc producing an adhesive barrier at the interface that improves adhesion between the liner and the oxide layer of the substrate; repeating the operations of depositing the monolayer of zinc and performing the thermal treatment until a predefined number of cycles is reached.

A method of depositing contiguous, conformal submonolayer-to-multilayer thin films with atomic-level control is described. The process involves the use of underpotential deposition of a first element to mediate the growth of a second material by overpotential deposition. Deposition occurs between a potential positive to the bulk deposition potential for the mediating element where a full monolayer of mediating element forms, and a potential which is less than, or only slightly greater than, the bulk deposition potential of the material to be deposited. By cycling the applied voltage between the bulk deposition potential for the mediating element and the material to be deposited, repeated desorption / adsorption of the mediating element during each potential cycle can be used to precisely control film growth on a layer-by-layer basis. This process is especially suitable for the formation of a catalytically active layer on core-shell particles for use in energy conversion devices such as fuel cells.

The invention relates to a modification method of a Pd membrane electrode based on formic acid electrooxidation. The modification method comprises the steps of carrying out underpotential deposition on the surface of Pd by utilizing Sb, depositing a single layer of Sb on the surface of a Pd substrate so as to improve a Pd surface structure, polishing a glassy carbon electrode on a piece of chamois leather to form a mirror surface, then carrying out electrochemical cleaning in 0.1M of HClO4 by adopting a cyclic voltammetry, depositing the Pd in a Pd plating solution, then carrying out controlled potential electrodeposition (0.2-0.3Vvs.SEC) in 0.1mM of antimony potassium tartrate (APT)+0.5M of H2SO4 for 10-30s, and depositing the single layer of Sb on the surface of the Pd substrate. Compared with the prior art, with the adoption of the modification method, the single layer of Sb is deposited on the surface of the Pd substrate by virtue of a simple UPD (Under Potential Deposition) technology, and the Pd electrode modified by the Sb has the relatively good catalytic effect on formic acid.

The invention discloses a Pt-Au@Pt core-shell structure fuel cell cathode catalyst and a preparation method thereof. The Pt-Au@Pt core-shell structure fuel cell cathode catalyst consists of a conductive carrier and Pt-Au@Pt core-shell structure nanoparticles. The preparation method comprises the following steps of: reducing a gold compound by using sodium borohydride to obtain Au nanoparticles, and loading the Au particles on the surface of a carbon carrier to obtain Au / C; and putting Au / C in a platinum compound water solution to obtain loaded-type Pt / Au alloy nanoparticles after Pt is subjected to spontaneous reductive deposition on the Au surface, depositing a Cu atom monolayer on the surface of the Pt-Au alloy nanoparticles by using an underpotential deposition method and then displacing the Cu atom monolayer with Pt to obtain the Pt-Au@Pt core-shell structure fuel cell cathode catalyst. The catalyst prepared by using the preparation method disclosed by the invention is high in catalytic activity and stability and low in cost relative to a pure Pt catalyst; and the preparation method is simple and convenient, mild in condition and easy to operate and can be used for solving the problem that a core-shell structure catalyst prepared by using a conventional chemical reduction method is high in Pt agglomeration degree on the surface and a catalyst prepared by using a single underpotential deposition method is low in Pt coverage degree on the surface.