Molybdenum carbide/foamed nickel composite material, preparation method, and application thereof in electrocatalytic oxygen evolution

Abstract

The invention discloses a molybdenum carbide / foamed nickel composite material, a preparation method, and application thereof in electrocatalytic oxygen evolution. The molybdenum carbide / foamed nickelcomposite material comprises molybdenum carbide and foamed nickel, and the molybdenum carbide is loaded on the foamed nickel. The preparation method of the molybdenum carbide / foamed nickel composite material comprises the following steps: preparing a molybdenum carbide precursor solution, covering the foamed nickel with a molybdenum carbide precursor, and calcining to obtain the molybdenum carbide / foamed nickel composite material. The molybdenum carbide / foamed nickel composite material has the advantages of large specific surface area, stable structure, good electrocatalytic performance and the like, is a novel electrocatalyst which is good in oxygen evolution effect, stable in performance and capable of being widely applied to electrocatalytic oxygen evolution, can be directly used as anelectrode material for electrocatalytic oxygen evolution reaction, and has very high use value and very good application prospect. The preparation method of the molybdenum carbide / foamed nickel composite material has the advantages of controllable preparation process, simple preparation process, low preparation cost and the like, is suitable for large-scale preparation, and is beneficial to industrial application.

Description

technical field [0001] The invention belongs to the field of electrocatalytic oxygen evolution materials, and relates to a molybdenum carbide / foam nickel composite material, a preparation method thereof and an application in electrocatalytic oxygen evolution. Background technique [0002] The water splitting reaction offers a promising avenue for the development of renewable energy mainly in the form of hydrogen fuel. The bottleneck of the water splitting reaction is the oxidation half-reaction, the oxygen evolution reaction (OER), which involves the participation of four consecutive electron and proton transfer steps, and has a high thermodynamic potential and a slow kinetic coefficient. At present, Ru- / Ir-based oxides are widely regarded as the most efficient catalysts for oxygen evolution reaction due to their excellent long-term catalytic activity, however, their widespread commercial applications are greatly hindered due to their scarcity and high cost. Therefore, effi...

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Problems solved by technology

[0003] Currently, molybdenum carbide as an electrocatalyst is mainly used for the hydrogen evolution reaction (HER) or oxygen reduction reaction (ORR), while the development of molybdenum carbide-based oxygen evolution electrocatalysts is still a challenging topic, mainly because of the d-band of Mo The electronic structure is similar to the noble metal Pt, and Pt is recognized as the most ideal electrocatalyst for the hydrogen evolution reaction. When this type of catalyst is used for the oxygen evolution reaction, the surface of the material will inevitably suffer from oxygen evolution corrosion, thereby reducing the oxygen evolution reaction. Therefore, in order to achieve high-efficiency oxygen evolution activity of molybdenum carbide-based electrocatalysts, the key is to solve the stability problem of the material in the electrolyte solution

In addition, the following problems still exist in the preparation process of molybdenum carbide-based catalysts (especially the nanocrystalline phase): the molybdenum carbide nanocrystals will aggregate and / or grow disproportionately at higher reaction temperatures, and the molybdenum carbide surface It is rapidly oxidized to molybdenum oxide (MoO x ) species, the existence of the above problems reduces the catalytic performance on the one hand, and complicates the research on the reaction mechanism on the other hand, which is not conducive to the promotion and application of molybdenum carbide-based catalysts.

For the improvement strategies of molybdenum carbide-based catalysts, such as metal or non-metallic doping, forming heterostructures, etc., although the above-mentioned improvement strategies can improve the oxygen evolution activity of molybdenum carbide-based catalysts, in the actual application process, the molybdenum carbide-based materials Aggregation / corrosion will lead to the loss of catalytic activity, and this problem has not been effectively solved; at the same time, the heterostructure strategy adopted above makes the preparation of the material more complicated on the one hand, and on the other hand makes the oxygen evolution reaction of the material more complex. The mechanism is more complicated; more seriously, the heteroatoms introduced by doping may cover the active sites on the molybdenum carbide, and the doping elements may be oxidized or overflow from the material during the catalytic reaction, so that the The catalytic performance is significantly reduced

In addition, the conductivity of electrode materials is a key factor in the design of electrocatalysts, and pure molybdenum carbide has poor conductivity, so it often needs to be coated on conductive substrates, such as silicon dioxide or glassy carbon electrodes, etc., but these conductive substrate materials Due to the lack of chemical bond connections, molybdenum carbide is easy to fall off during electrocatalysis, resulting in reduced catalytic performance, that is, the existing molybdenum carbide-based composite materials have the problem of poor stability

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