CoS2 isomeric composite material as well as preparation method and application thereof

Abstract

The invention aims to provide a CoS2 isomeric composite catalytic material as well as a preparation method and application thereof, and belongs to the technical field of preparation of bifunctional catalyst materials. According to the homogeneous and heterogeneous composite material, the CoS2 octahedral particles are attached to the CoS2 nanotubes, the component is single, the structure is multi-stage, compared with a single-structure material, the nanotubes can provide an electron transmission path for water electrolysis reaction on the surfaces of the octahedral particles, the octahedral particles have the characteristic of high-density grain boundaries, and the homogeneous and heterogeneous composite material can be applied to the field of water electrolysis reaction of the surfaces of the octahedral particles. The exposed specific crystal face structure and boundary defects provide a large number of active sites for catalytic reaction. When an electrode loaded with the homogeneous and heterogeneous composite material is subjected to a catalytic hydrogen evolution reaction in a 0.5 M H2SO4 solution, the current density of 10mA cm <-2 > only needs an overpotential of 161mV; when oxygen evolution reaction occurs in a 1M KOH solution, the overpotential of 10mA cm <-2 > current density is 272 mV, which proves that the material can be used as a hydrogen evolution electrode and also can be used as an oxygen evolution electrode and has double functions.

Description

technical field [0001] The invention belongs to the technical field of preparation of bifunctional catalyst materials, and in particular relates to a CoS 2 Nanotube and octahedral particle isomeric composite material and preparation method thereof, and its application in electrocatalytic water splitting reaction. Background technique [0002] In the prior art, electrolysis of water is the most ideal method for large-scale hydrogen production, but the electrochemical hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) involved in it have high overpotentials, resulting in high electrolysis energy consumption. The energy efficiency of hydrogen production is low, and it is difficult to achieve large-scale application. High-performance electrocatalysts are the key to solving the problem of high overpotentials in hydrogen evolution and oxygen evolution reactions. Studies have shown that the catalyst composite electrode can effectively reduce the electrolysis ov...

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Problems solved by technology

Huang et al. (Journal of Materials Chemistry A, 2015, 3, 22886-22891) reported a hydrothermal method for the preparation of CoS 2 The method of nanorods, the method takes the precipitated matter to wash after the hydrothermal reaction, and vacuum-dries to obtain nanorods, and the prepared catalytic electrode is heated in 0.5M H 2 SO 4 10mA cm is generated when hydrogen evolution reaction occurs in the solution -2 The overpotential of current density is 288mV, but the overpotential of this catalyst is still higher; Patent CN112194192A discloses a kind of CoS 2 A controllable preparation method for nanotubes. In this method, the product after the first hydrothermal reaction is purified by ultrasonic washing, and then placed in a chemical vapor deposition system together with a sulfur source. By adjusting Ar / H 2 The gas ratio can realize the regulation of nanorod to nanotube morphology, but this preparation method cannot grow more complex nanostructures in situ on nanorods or nanotubes; Tang et al. (Journal of Materials ChemistryA, 2019, 7, 13339 - 13346) reported the preparation of CoS by a two-step hydrothermal method 2 The nanotube method, the precipitation product after the first step of hydrothermal washing, vacuum drying to obtain CoS 2 Nanorods, and then through the second step of hydrothermal reaction and annealing treatment to obtain CoS 2 Nanotubes, this method achieves structural evolution from nanorods to nanotubes, but cannot obtain multi-level nanostructured composites; Wan et al. The precipitated material was purified, washed, and vacuum-dried to prepare CoS 2 Octahedral particle method, which in 0.5M H 2 SO 4 10mA cm is generated when hydrogen evolution reaction occurs in the solution -2 The overpotential of the current density is 173mV, and its catalytic activity is better than that of CoS 2 Nanorods and nanotubes, but there is still room for improvement

Synthesis of nanostructured CoS by hydrothermal reaction 2 In the end, only nanorods, nanotubes or nanoparticles with a single structure were prepared, which did not realize the complexity of the material structure and the order of magnitude expansion of the surface area. The performance of the catalyst is limited

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