阅读说明：本技术 一种四重修饰的二硫化钼电催化剂及制备方法 (Quadruple-modified molybdenum disulfide electrocatalyst and preparation method thereof ) 是由 林志萍 申士杰 钟文武 吴建波 王宗鹏 于 2019-11-23 设计创作，主要内容包括：本发明公开一种四重修饰二硫化钼电催化剂的方法,包括以下步骤：前驱体的准备；脉冲激光辐照处理。本发明还公开一种四重修饰的二硫化钼电催化剂,其采用如上所述的方法制备而成,运用于催化析氢领域。(The invention discloses a method for quadruple modification of a molybdenum disulfide electrocatalyst, which comprises the following steps: preparing a precursor; and (5) performing pulsed laser irradiation treatment. The invention also discloses a quadruple modified molybdenum disulfide electrocatalyst which is prepared by adopting the method and is applied to the field of catalytic hydrogen evolution.)

1. A method for quadruple modification of a molybdenum disulfide electrocatalyst, comprising the steps of: using the purchased molybdenum disulfide which is not further treated as a precursor; the precursor 1 g obtained is flatly laid on SiO₂In the groove of the component, the size of the groove is 1 square centimeter; adopting pulse laser with power density of 2.5W/sq cm and wavelength of 532 nm to perform scanning irradiation on the sample uniformly, then laying the sample flat again, performing repeated laser scanning on the sample for 5 times, and ensuring that the sample is scanned uniformly by the laser; and obtaining the required quadruple modified molybdenum disulfide electrocatalyst after laser treatment.

2. The molybdenum disulfide electrocatalyst prepared by the method of claim 1, wherein molybdenum disulfide quantum dots having a diameter of less than 10 nm are formed in situ on a molybdenum disulfide platelet; the quantum dots are aggregated into molybdenum disulfide nano particles with the diameter of dozens of nanometers, and the crystal boundary between the quantum dots is amorphized; the existence of defects; discrete molybdenum disulfide quantum dots are present.

Technical Field

The invention relates to a quadruple modified molybdenum disulfide electrocatalyst and a preparation method thereof.

Technical Field

The increasing environmental crisis and global energy shortages force people to find new sources of sustainable regeneration that can replace traditional fuels. Hydrogen energy has become one of the energy substitutes for conventional fuels because of its non-polluting combustion products, high fuel value and stable storage on a large scale. Hydrogen production by electrocatalysis decomposition of water is an environment-friendly and efficient hydrogen production method.

The efficiency of electrocatalytic hydrogen production depends on the electrocatalyst used to accelerate the progress of the hydrogen production reaction. One of the criteria used to characterize the performance of electrocatalysts is overpotential. The excessive overpotential will cause the consumption of excessive electric energy in the process of hydrogen production by electrocatalytic decomposition of water, so how to further reduce the overpotential of the electrocatalyst becomes a difficult point in the field.

Disclosure of Invention

The invention aims to reduce the overpotential of a molybdenum disulfide electrocatalyst, and provides a method for efficiently preparing a quadruple modified molybdenum disulfide electrocatalyst. The implementation of the invention comprises the following steps: the precursor 1 g obtained is flatly laid on SiO₂In the groove of the component, the size of the groove is 1 square centimeter; adopting pulse laser with power density of 2.5W/sq cm and wavelength of 532 nm to perform scanning irradiation on the sample uniformly, then laying the sample flat again, performing repeated laser scanning on the sample for 5 times, and ensuring that the sample is scanned uniformly by the laser; and obtaining the required quadruple modified molybdenum disulfide electrocatalyst after laser treatment.

Compared with the prior art, the sample provided by the invention has the following advantages: firstly, a molybdenum disulfide electrocatalyst with a lower overpotential can be obtained. The double and quadruple modified molybdenum disulfide exposes more reaction interfaces and boundary atoms.

Drawings

FIG. 1 is an X-ray diffraction pattern of comparative example and example.

FIG. 2 is a common transmission electron micrograph of comparative example and example.

FIG. 3 is a high-resolution transmission electron micrograph of the embodiment; wherein, FIG. 3A, FIG. 3C and FIG. 3E are transmission electron microscope images of three characteristic regions of the embodiment, respectively, FIG. 3B is a partial enlarged view of FIG. 3A; FIG. 3D is an enlarged view of a portion of FIG. 3C; fig. 3F is a partially enlarged view of fig. 3E.

FIG. 4 is a graph showing the overpotential curves of the comparative example and the example.

Detailed Description

The following describes the implementation of the present invention in detail with reference to specific embodiments.

The specific steps of this example are as follows: the precursor 1 g obtained is flatly laid on SiO₂In the groove of the component, the size of the groove is 1 square centimeter; using a power density of 2.5 watts/square centimeter, wavePulse laser with the length of 532 nanometers is used for carrying out uniform scanning irradiation on a sample, then the sample is paved again, repeated laser scanning is carried out on the sample for 5 times, and the sample is ensured to be uniformly scanned by the laser; and obtaining the required quadruple modified molybdenum disulfide electrocatalyst after laser treatment.

To illustrate the technical effect of this example, molybdenum disulfide was purchased without further treatment as a comparative example of this example.

Diffraction data were measured by an X-ray diffraction method for samples obtained in accordance with examples and comparative examples. It can be seen that the comparative sample has very good crystallinity with several distinct characteristic diffraction peaks at 14.4 °, 29.0 °, 39.6 °, 44.2 °, 49.8 ° and 60.2 ° compared to PDF #37-1492 (MoS)₂, P6₃/mmc,a= 3.161 Å,cThe diffraction peaks of (002), (004), (103), (006), (105) and (008) in = 12.299 Å) corresponded well the positions of the diffraction peaks of the samples in the examples were almost unchanged, but the intensities were significantly changed, and the strongest (002) diffraction peak had an intensity of less than MoS which was not quadrupled modified₂One third of the total.

FIG. 2 is a common transmission electron micrograph of comparative example and example. Fig. 2A shows that the comparative example has a distinct lamellar structure, with dimensions between nanometers and micrometers. Figure 2B shows that the embodiment also has a distinct sheet-like structure. Under the action of laser, part of the small-sized molybdenum disulfide nanosheets are in a disc shape. It is particularly noted that the example surface presents nanoparticles with diameters of a few tens of nanometers.

FIG. 3 is a high-resolution TEM image of the example. It can be seen in fig. 3A and 3B that nanoparticles with a surface diameter of several tens of nanometers are composed of molybdenum disulfide quantum dots with a diameter of less than 10 nanometers; in fig. 3C and 3D, it can be seen that discrete molybdenum disulfide quantum dots are distributed beside the nanoparticles, corresponding to the enlarged shaded portion in fig. 3D; it is clear from fig. 3E and 3F that there are significant defects at the interface between adjacent quantum dots, and the grain boundaries between the quantum dots are amorphized. The aggregation of quantum dots into nanoparticles, discrete molybdenum disulfide quantum dots, and amorphization and defects of grain boundaries between quantum dots result from the removal of quenching after laser irradiation. The quadruple modification of the surface of the molybdenum disulfide electrocatalyst brings more reaction interfaces and boundary atoms for the molybdenum disulfide electrocatalyst, and is favorable for improving the electrocatalytic performance.

FIG. 4 shows a comparative investigation of the overpotentials of the examples and comparative examples, typically at a current density of-10 mA/cm²The overpotentials at time were compared. The overpotential of the comparative example is 461 mV, the overpotential of the example is obviously optimized, and the value of the overpotential is directly reduced to 217 mV.

In summary, a quadruple modified molybdenum disulfide electrocatalyst can be prepared by the method as described in the examples.

The invention also discloses a quadruple modified molybdenum disulfide electrocatalyst which is prepared by adopting the method in the embodiment. The quadruple modified molybdenum disulfide electrocatalyst has an overpotential of 217 mV (at-10 mA/cm)²At current density) is significantly better than unmodified molybdenum disulfide.

It should be noted that the above description is only a preferred embodiment of the present invention, and the present invention is not limited to the above examples. It is to be understood that other modifications and variations, which may be directly derived or suggested to one skilled in the art without departing from the basic concept of the invention, are to be considered as included within the scope of the invention.