Molybdenum disulfide quantum dot modified molybdenum carbide/foamed nickel composite material, preparation method and application of the composite material in electrocatalytic oxygen evolution

Abstract

The invention discloses a molybdenum disulfide quantum dot modified molybdenum carbide/foamed nickel composite material, a preparation method and application of the composite material in electrocatalytic oxygen evolution. The composite material comprises a molybdenum carbide/foamed nickel composite material formed by loading molybdenum carbide on foamed nickel, and molybdenum disulfide quantum dots being grown on the surface of the molybdenum carbide/foamed nickel composite material. The preparation method comprises the following steps of: preparing a molybdenum disulfide quantum dot precursorsuspension; mixing the molybdenum disulfide quantum dot precursor suspension with the molybdenum carbide/foamed nickel composite material; and carrying out hydrothermal reaction to obtain the composite material. The composite material has the advantages of being stable in structure, good in 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 an electrode material for an electrocatalytic oxygen evolution reaction, and has very high use value and very good application prospects. The preparation method 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 modified by molybdenum disulfide quantum dots, 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 ...

AI Technical Summary

Problems solved by technology

[0003] MoS2 exhibits better hydrogen evolution performance in the Volmer reaction of the hydrogen evolution reaction (HER) due to its lower Gibbs free energy of hydrogen adsorption (ΔG) at its catalytically active edge, even comparable to that of Pt. , there are very few studies on the oxygen evolution reaction of molybdenum disulfide-based catalysts. In order to develop the oxygen evolution performance of molybdenum disulfide, researchers have widely used three-dimensional transition metal sulfides, oxides or hydroxides molybdenum hybridization method to prepare bifunctional molybdenum disulfide-based catalysts that can realize hydrogen evolution and oxygen evolution at the same time, but in these catalytic systems, the hydrogen evolution activity comes from molybdenum disulfide, while the oxygen evolution activity is mainly attributed to Other components of the hybrid, not molybdenum disulfide itself

[0004] Molybdenum carbide as an electrocatalyst is mainly used for hydrogen evolution reaction (HER) or oxygen reduction reaction (ORR), while the development of oxygen evolution electrocatalysts based on molybdenum carbide is still a challenging topic, mainly because of the d-band electronic structure of Mo. Similar to the noble metal Pt, 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 performance. Therefore, in order to realize the 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

[0005] In addition, the conductivity of electrode materials is a key factor in the design of electrocatalysts. Pure molybdenum disulfide or molybdenum carbide has poor conductivity and often needs to be coated on conductive substrates, such as silicon dioxide or glassy carbon electrodes. However, these Due to the lack of chemical bond connection of conductive substrate materials, molybdenum disulfide and molybdenum carbide are easy to fall off during electrocatalysis, resulting in reduced catalytic performance, that is, the existing molybdenum disulfide or molybdenum carbide-based composite materials have poor stability. Structural instability in molybdenum composites

Images