A method for making a three-dimensional hierarchical layered porous copper, the method includes providing a copper-zinc alloy precursor being composed of a β′ phase and a γ phase, and treating the copper-zinc alloy precursor by electrochemical dealloying. The present application further provides a three-dimensional hierarchical layered porous copper including a first surface layer, an intermediate layer, and a second surface layer stacked in that order. The first surface layer includes a plurality of micron-scale pores and a plurality of first nanoscale pores. The intermediate layer includes a plurality of second nanoscale pores. The second surface layer includes the plurality of micron-scale pores and the plurality of first nanoscale pores.

A method for making a three-dimensional hierarchical layered porous copper, the method includes providing a copper-zinc alloy precursor being composed of a β′ phase and a γ phase, and treating the copper-zinc alloy precursor by electrochemical dealloying. The present application further provides a three-dimensional hierarchical layered porous copper including a first surface layer, an intermediate layer, and a second surface layer stacked in that order. The first surface layer includes a plurality of micron-scale pores and a plurality of first nanoscale pores. The intermediate layer includes a plurality of second nanoscale pores. The second surface layer includes the plurality of micron-scale pores and the plurality of first nanoscale pores.

A manufacturing method of copper foil and circuit board assembly for high frequency transmission are provided. Firstly, a raw copper foil having a predetermined surface is produced by an electrolyzing process. Subsequently, a roughened layer including a plurality of copper particles is formed on the predetermined surface by an arsenic-free electrolytic roughening treatment and an arsenic-free electrolytic surface protection treatment. Thereafter, a surface treatment layer is formed on the roughened layer, and the roughened layer is made of a material which includes at least one kind of non-copper metal elements and the concentration of the non-copper metal elements is smaller than 400 ppm. By controlling the concentration of the non-copper elements, the resistance of the copper foil can be reduced.

A manufacturing method of copper foil and circuit board assembly for high frequency transmission are provided. Firstly, a raw copper foil having a predetermined surface is produced by an electrolyzing process. Subsequently, a roughened layer including a plurality of copper particles is formed on the predetermined surface by an arsenic-free electrolytic roughening treatment and an arsenic-free electrolytic surface protection treatment. Thereafter, a surface treatment layer is formed on the roughened layer, and the roughened layer is made of a material which includes at least one kind of non-copper metal elements and the concentration of the non-copper metal elements is smaller than 400 ppm. By controlling the concentration of the non-copper elements, the resistance of the copper foil can be reduced.

Provided is a post-treatment method and system for a core-shell catalyst, which relate to the field of fuel cell materials. The post-treatment method of the present disclosure includes the following steps: a core-shell catalyst is added into an electrolyte solution containing citric acid or ethylenediamine tetraacetic acid, a gas containing oxygen is introduced into the electrolyte solution followed by stirring for a predetermined reaction time, the open circuit potential of the reactor base is recorded during the reaction time, and the open circuit potential should stabilize at 0.90˜1.0 V vs. RHE when the reaction is completed. The molar ratio of citric acid or ethylenediamine tetraacetic acid to platinum of the core-shell catalyst is 10 to 1000:1. A percentage of oxygen in the gas is 10 to 100% by volume. The post-treatment method of the present disclosure can significantly improve the platinum mass activity and PGM mass activity and durability of core-shell catalyst.

A method for 3D printing includes printing a first metallic material on a substrate as a support structure (48). A second metallic material, which is less anodic than the first metallic material, is printed on the substrate as a target structure (46), in contact with the support structure. The support structure is chemically removed from the target structure by applying a galvanic effect to selectively corrode the first metallic material.

A nanoporous metal structure is made by etching a metal alloy structure of two or more metals. Less than all of the metals are selectively removed (e.g., dissolved in solution) from the alloy in the presence of an alternating voltage profile, for example, a periodic voltage profile. The resulting nanoporous metal structure, having pore openings of about 20 nm to about 500 nm in diameter and a purity of at least about 70%, can be further treated to alter some or all of the structure, and/or to add, remove and/or modify properties thereof.

A nanoporous metal structure is made by etching a metal alloy structure of two or more metals. Less than all of the metals are selectively removed (e.g., dissolved in solution) from the alloy in the presence of an alternating voltage profile, for example, a periodic voltage profile. The resulting nanoporous metal structure, having pore openings of about 20 nm to about 500 nm in diameter and a purity of at least about 70%, can be further treated to alter some or all of the structure, and/or to add, remove and/or modify properties thereof.

The present invention relates to surface roughening methods and more particularly to a method for electrochemical roughening of thin film macro- and micro-electrodes. In one embodiment, an electrochemical etch template is formed comprising polymer particles adsorbed on a surface of a substrate to be roughened, followed by electrochemically etching of exposed regions of the substrate between the polymer particles in the electrochemical etch template so as to selectively roughen the surface of the substrate. In another embodiment, a surface of the electrode is immersed in either a adsorbing acidic solution, such as sulfuric acid, or a non-adsorbing acidic solution, such as perchloric acid, followed by electrochemically pulse etching the surface of the substrate at a narrow frequency range for adsorbing acidic solutions, or at a wide frequency range for non-adsorbing acidic solutions.

A capacitor has an anode with one or more active layers that each includes fused particles positioned on a current collector. The current collector includes tunnels that extend from a first face of the current collector to a second face of the current collector.