A method for surface alloy modification of nanoporous gold

Abstract

The invention relates to a method for carrying out surface alloy modification upon nano-grade porous gold. According to the method, an alloy material is deposited on the surface of nano-grade porous gold with a pulse potential method. The method has the steps that: the nano-grade porous gold is connected on an electrode, and is placed in a solution with different metal ions; pulse potential is applied, wherein the pulse skips between a high potential and a low potential; the high potential is fixed at a value with which the different metal ions are not reduced, and the low potential is fixed at a value with which the metal ions in the solution can be reduced; the two potentials form a pulse cycle; and through multiple times of cycles, the alloy modification upon the nano-grade porous gold is completed. With the method, the nano-grade porous gold is subjected to alloy modification. The prepared nano-grade porous gold based catalyst has low platinum load, high activity, high intoxication resistance, and high corrosion resistance.

Description

technical field [0001] The invention belongs to the technical field of electrochemistry and relates to a method for surface alloy modification of nanoporous gold. Background technique [0002] A fuel cell is a clean and efficient energy conversion device. Through electrochemical reactions, the energy in the fuel can be converted into electricity. Proton exchange membrane fuel cells are particularly suitable as power devices for mobile devices due to their advantages such as low operating temperature, compact structure, and no noise. However, since both the cathode and the anode of the proton exchange membrane fuel cell need to use the noble metal platinum as a catalyst, the price of the fuel cell is relatively high. In addition, the currently widely used carbon-supported platinum catalysts will suffer from corrosion of carbon supports and agglomeration of platinum nanoparticles during use, and the stability needs to be improved urgently. For direct alcohol (or direct acid...

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Problems solved by technology

The gas-liquid phase electroless plating method is to place nanoporous gold in a specific metal ion solution, and then reduce the noble metal ions to the surface of nanoporous gold under the hydrazine hydrate atmosphere. This method is simple and easy, but hydrazine hydrate is needed during the experiment. High toxicity; underpotential deposition combined with displacement method mainly uses underpotential deposition method to first deposit more active metals (such as copper, silver) on the surface of nanoporous gold, and then uses in situ displacement reaction to remove the less active components in the solution Ion reduction modification to the surface of nanoporous gold, this method is limited by the electrode potential of the material, the types of metals that can be deposited are limited, and the method is cumbersome, and it is difficult to deposit alloys; the molecular adsorption method is to put the nanoporous metal material into the plating solution and soak it After a period of time, the metal ions in the plating solution will be adsorbed on the surface of nanoporous gold, and then the potential will be applied to reduce the noble metal ions. This method can deposit sub-monatomic layer noble metals, which is accurate and controllable, but it can only be deposited with nanoporous gold. Metals adsorbed to each other, other metals are difficult to deposit; the constant potential or constant current electrochemical deposition method mainly applies a constant current or voltage to restore the metal to the surface of nanoporous gold, but is limited by the three-dimensional nanostructure of nanoporous gold. Scale pore structure, the metals deposited by this method are usually enriched on the outer surface of nanoporous gold, and it is difficult to uniformly modify the inner surface

In addition, all the above methods are difficult to realize the composition-controllable surface alloying modification of nanoporous gold.

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