CN108796553B

CN108796553B - Tetragonal phase CoSe for catalytic hydrogen evolution and preparation method thereof

Info

Publication number: CN108796553B
Application number: CN201810715957.2A
Authority: CN
Inventors: 林志萍; 钟文武; 申士杰; 王宗鹏; 徐爱娇; 詹白勺
Original assignee: Taizhou University
Current assignee: Taizhou University
Priority date: 2018-06-29
Filing date: 2018-06-29
Publication date: 2020-05-22
Anticipated expiration: 2038-06-29
Also published as: CN108796553A

Abstract

The invention discloses a preparation method of a tetragonal CoSe electrocatalyst for catalyzing hydrogen evolution reaction, which comprises the following steps: preparing materials; preparation of KCo₂Se₂Raw materials; system for makingPreparing a saturated LiOH solution; tetragonal CoSe was prepared. The invention also discloses a tetragonal CoSe electrocatalyst which is prepared by the method and is applied to the field of catalytic hydrogen evolution.

Description

Tetragonal phase CoSe for catalytic hydrogen evolution and preparation method thereof

Technical Field

The invention relates to the application field of electrocatalytic materials, in particular to tetragonal CoSe for catalyzing hydrogen evolution and a preparation method thereof.

Technical Field

With the shortage of energy resources and the increasing severity of environmental pollution, the research on sustainable clean energy has attracted much attention. Among clean energy, hydrogen is an ideal energy material because the combustion product is water, has high energy storage density and is rich in earth hydrogen elements. Electrocatalytic hydrogen evolution reactions, i.e. obtaining hydrogen by electrocatalytic decomposition of water, are considered as an efficient way to obtain hydrogen. In the electrocatalytic hydrogen evolution reaction, the electrocatalyst plays a decisive role, and the design and search of the electrocatalyst with low cost and high efficiency are important for pushing the hydrogen energy to practical application. Noble metals are mostly good catalytic materials. At present, platinum is the catalyst with the highest catalytic hydrogen evolution activity in an acid environment, but the application of platinum materials is greatly limited due to the high price and the scarcity of platinum elements. Besides noble metals, elements or compounds rich on earth, such as transition metal sulfides, selenides, etc., have also been widely studied.

The hexagonal cobalt sulfide compound has poor electrocatalytic performance, and the application of the cobalt sulfide compound in the electrocatalytic field is severely restricted.

Disclosure of Invention

The invention aims to provide a tetragonal CoSe electrocatalyst for catalyzing hydrogen evolution reaction, which has good electrocatalytic hydrogen evolution performance, aiming at the problem that hexagonal CoSe has poor electrocatalytic hydrogen evolution performance.

The implementation of the invention comprises the following steps.

① the material is prepared by removing surface oxide layer with scissors in argon protection atmosphere by using 99.8% of block K, 99.9% of Co powder, 99.999% of Se powder and 98% of LiOH particles.

② preparation of KCo₂Se₂Raw materials: firstly, mixing the following components in proportion K: co: se = 1: 2: 2 weighing raw materials, mixing and grinding Co powder and Se powder. And pouring the mixture of the Co powder and the Se powder into a die, then pressing the mixture into tablets by using a tablet press (the pressure reaches 8 MPa), and releasing the pressure after keeping the pressure for 10 minutes. The pressed sheet mixture is knocked into two pieces with equal size and is placed into a crucible. Cutting the weighed K blocks into a plurality of small blocks, putting the small blocks into the crucible together, and covering the top of the crucible with a crucible cover. The crucible was placed in a quartz tube, and after high purity argon gas of 0.2 atm was filled in the quartz tube, the quartz tube was sealed. Heating the sealed quartz tube to 1000 ℃ for 4 hours, reacting at 1000 ℃ for 4 hours, quenching in water, and rapidly cooling. Subjecting the obtained KCo₂Se₂The raw materials are ground into a powder.

③ saturated LiOH solution is prepared by preparing a saturated LiOH solution from LiOH particles having a purity of 98%.

④ the process is carried out in a glove box to prevent KCo₂Se₂And (4) deterioration. After the glass bottle was allowed to stand for 2 days, the obtained sample was centrifugally washed three times to obtain a tetragonal CoSe sample.

⑤ preparing hexagonal CoSe is prepared through weighing Co powder and Se powder in the ratio of Co to Se = 1:.1, mixing, grinding, tabletting for 10 min, releasing pressure, sealing in a quartz tube filled with high-purity argon gas of 0.2 atm, heating to 850 deg.c for 10 hr, and reaction at 850 deg.c for 48 hr, and cooling in furnace to room temperature to obtain tetragonal CoSe sample.

The grinding used in the above steps is carried out by using an apparatus such as a mortar or a ball mill, preferably a ball mill.

Compared with the prior art, the sample synthesis method has the following advantages: by KCo₂Se₂The raw materials are as followsUnder the action of saturated LiOH solution, the tetragonal CoSe material is prepared and has good electrocatalytic performance. II, in the preparation of KCo₂Se₂In the raw material process, the quartz tube is heated to 1000 ℃ for 4 hours, and after the quartz tube reacts for 4 hours at 1000 ℃, the quartz tube is quenched in water for rapid cooling, so that rapid preparation of KCo can be realized₂Se₂Powder, which is helpful for practical production application of tetragonal CoSe material.

Drawings

FIG. 1X-ray diffraction patterns of tetragonal and hexagonal phase CoSe.

FIG. 2 Linear sweep voltammograms of tetragonal and hexagonal phase CoSe.

FIG. 3 Tafel slope plots of tetragonal and hexagonal phase CoSe.

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:

④ preparation of tetragonal CoSe ground KCo₂Se₂The powder was poured into a glass bottle containing saturated LiOH solution and the bottle cap was closed. The process needs to be carried out in a glove box to prevent KCo₂Se₂And (4) deterioration. After the glass bottle was allowed to stand for 2 days, the obtained sample was centrifugally washed three times to obtain a tetragonal CoSe sample.

To illustrate the technical effects of this example, a sample was prepared as a comparative example of this example according to the following procedure:

② preparation of KCo₂Se₂Raw materials: firstly, mixing the following components in proportion K: co: se = 1: 2: 2 weighing raw materials, mixing and grinding Co powder and Se powder. And pouring the mixture of the Co powder and the Se powder into a die, then pressing the mixture into tablets by using a tablet press (the pressure reaches 8 MPa), and releasing the pressure after keeping the pressure for 10 minutes. The pressed sheet mixture is knocked into two pieces with equal size and is placed into a crucible. Cutting the weighed K blocks into a plurality of small blocks, putting the small blocks into the crucible together, and covering the top of the crucible with a crucible cover. The crucible was placed in a quartz tube, and after high purity argon gas of 0.2 atm was filled in the quartz tube, the quartz tube was sealed. Heating the sealed quartz tube to 1000 ℃ for 4 hours, and reacting at 1000 DEG CAfter a lapse of 4 hours, the steel sheet was quenched in water and rapidly cooled. Subjecting the obtained KCo₂Se₂The raw materials are ground into a powder.

Diffraction data were measured by X-ray diffraction method for the samples obtained in the examples and comparative examples, respectively (test conditions: use of a Cu target as a radiation source at room temperature; setting of an instrument voltage of 40 KV and a current of 40 mA; test from 10 ℃ to 80 ℃). The X-ray diffraction spectrum of tetragonal CoSe is shown in fig. 1, and the diffraction data can be indexed by space group I4/mmm, and the indexed lattice constant is:a=3.708(1) Å，c=5.348(2) Å X-ray diffraction spectrum of hexagonal phase CoSe as shown in fig. 1, diffraction data can be indexed, and a space group can be usedP6₃ /mmcIndexing is carried out, and the indexed lattice constant is as follows:a=3.620(1) Å，c=5.293(1) Å. the indexing results further illustrate that tetragonal and hexagonal phase CoSe were successfully prepared.

Linear sweeping of tetragonal and hexagonal phase CoSeThe sweep rate of the test was 5 mV/s, as shown in FIG. 2. As can be seen from the figure, the hexagonal phase CoSe is at 10 mA/cm²The overpotential of the current density relative to the reversible hydrogen electrode is 352mV, and the tetragonal phase CoSe is 10 mA/cm²The overpotential at current density relative to the reversible hydrogen electrode was 175 mV, indicating that tetragonal phase CoSe has better electrocatalytic capacity than hexagonal phase CoSe.

Tafel slope data for tetragonal and hexagonal phase CoSe As shown in FIG. 3, the Tafel slope for hexagonal phase CoSe is 105mV dec^-1The Tafel slope of the tetragonal CoSe phase is 36mV dec^-1Further illustrates that tetragonal phase CoSe has better electrocatalytic capacity than hexagonal phase CoSe.

In summary, a tetragonal CoSe electrocatalyst for catalyzing hydrogen evolution reactions can be prepared by the methods described in the examples.

The invention also discloses tetragonal CoSe for catalyzing hydrogen evolution, which is prepared by adopting the method in the embodiment. The compound has an overpotential of 352mV (at 10 mA/cm)²At current density), the Tafel slope is 36mV dec^-1。

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.

Claims

1. The application of tetragonal CoSe in the field of electrocatalytic hydrogen evolution is characterized in that the tetragonal CoSe is prepared by the following steps:

① preparing material, namely removing surface oxide layers by using a pair of scissors in an argon protective atmosphere by using block K with the purity of 99.8%, Co powder with the purity of 99.9%, Se powder with the purity of 99.999% and LiOH particles with the purity of 98%;

② preparation of KCo₂Se₂Raw materials: firstly, mixing the following components in proportion K: co: se = 1: 2: 2 weighing the raw materials, mixing and grinding Co powder and Se powder, and mixing the Co powder and the Se powderPouring the mixture into a mold, pressing the mixture into tablets by a tablet press, keeping the pressure of the tablets to 8MPa, releasing the pressure after 10 minutes, knocking the pressed mixture into two pieces with equal size, putting the two pieces into a crucible, cutting the weighed K pieces into a plurality of small pieces, putting the small pieces into the crucible together, covering the top of the crucible with a crucible cover, putting the crucible into a quartz tube, filling high-purity argon gas with 0.2 atmospheric pressure into the quartz tube, sealing the quartz tube, heating the sealed quartz tube to 1000 ℃ for 4 hours, reacting at 1000 ℃ for 4 hours, quenching in water for rapid cooling, and obtaining the KCo₂Se₂Grinding the raw materials into powder;

③ preparing saturated LiOH solution, preparing saturated LiOH solution from LiOH particles with the purity of 98%;

④ preparation of tetragonal CoSe ground KCo₂Se₂Pouring the powder into a glass bottle filled with saturated LiOH solution, covering the bottle with a bottle cap, wherein the process needs to be carried out in a glove box to prevent KCo₂Se₂Performing deterioration, namely standing the glass bottle for 2 days, and then centrifugally cleaning the obtained sample for three times to obtain a tetragonal CoSe sample; the grinding is carried out by adopting a ball mill.