A nickel-cobalt binary catalyst promoting the direct oxidation of sodium borohydride

Abstract

A kind of nickel-cobalt binary catalyst that promotes the direct oxidation of sodium borohydride is characterized in that: (1) under normal temperature and pressure, prepare 0.2mol / dm 3 nickel chloride (NiCl 2 ·6H 2 O), 0.0000~0.0300mol / dm 3 Cobalt Chloride (CoCl 2 ·6H 2 O) and 4mol / dm 3 Ammonium chloride (NH 4 The mixed solution of Cl) is an electrodeposition solution; (2) Assembling a two-electrode system: a 1cm×2cm polished Ni sheet is placed in the above solution as a cathode, wherein the working area of ​​the Ni sheet is 1cm×1cm, and a carbon rod (3) Using the constant current method, in a constant temperature water bath at 298.15K, with a deposition current of 2A, and a deposition time of 20s, deposit Ni and Co on the above smooth Ni sheet. The nickel-cobalt catalyst prepared by electrodeposition has a porous structure, and the addition of cobalt makes the catalyst have a larger average pore size and porosity, which significantly increases the specific surface area, increases the number of catalytic active sites, and reduces the resistance to be overcome in the direct oxidation reaction. The charge transfer of the electrode reaction is enhanced; at the same time, the discharge potential of the fuel is reduced, the discharge efficiency of the fuel is significantly improved, and the oxidation performance of the fuel is improved.

Description

technical field [0001] The invention belongs to the field of electrochemical applications, and in particular relates to the preparation of a nickel-cobalt binary catalyst for direct oxidation of sodium borohydride by an electrodeposition method, and the sodium borohydride is the negative electrode active material of the direct sodium borohydride fuel cell, that is, the fuel of the battery. Background technique [0002] A direct borohydride fuel cell (DBFC) is a fuel cell that stores borohydride ( ) is a new type of fuel cell in which the chemical energy in the anode catalyst is directly converted into electrical energy. It has a series of advantages such as high open circuit voltage, large specific capacity and high energy conversion rate, convenient transportation, can work at room temperature, non-toxic, and safe transportation. . However, as far as the current research progress is concerned, there are still some problems: ① During the electrochemical oxidation, the ac...

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Problems solved by technology

However, as far as the current research progress is concerned, there are still some problems: ① During the electrochemical oxidation, the accompanying water decomposes hydrogen, resulting in a decrease in fuel utilization and an increase in the open circuit potential of the anode; ②When the battery is working, The "penetration" phenomenon of fuel loss and cathode performance degradation

However, when Ni is used as an anode catalyst in the prior art, because Ni is easily corroded in an alkaline environment, it loses its catalytic activity, resulting in BH 4 - The electrochemical reaction impedance during direct oxidation is large, the charge transfer resistance of the electrode reaction is large, and the reaction rate is slow. The direct oxidation performance is not high, and the fuel discharge efficiency is low

Studies have shown that the catalytic performance of binary catalysts is often better than that of single-element metal catalysts. Current research has found that binary catalysts composed of noble metals and noble metals, such as Au-Pt, Au-Pd, Pd-Ag, etc., or Ni and noble metals Binary catalysts such as Ni-Au, etc., they have good catalytic ability, but the price is high and the cost is high

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