阅读说明：本技术 防锈剂分子制备双功能电解水催化剂的方法 (Method for preparing bifunctional electrolytic water catalyst by using antirust agent molecules ) 是由 詹天荣 叶琳 王军 钱星 王超 温永红 王磊 于 2021-08-20 设计创作，主要内容包括：本发明利用防锈剂分子2,4,6-三(氨基己酸基)-1,3,5-三嗪对金属离子的强络合作用,以及加热过程中释放出氨气提供碱性条件的特性,先制备钴铁类水滑石/碳,再进行低温硫化制备得到了硫化钴/钴铁类水滑石/纳米碳双功能催化剂。该方法避免了有机分子衍生碳基催化剂严苛的高温条件,前驱体溶液中金属络合物的分子特性能使金属种类纳米粒子均匀地分散在纳米碳载体上,增加比表面积和活性位点,以及金属种类与碳材料之间的接触和相互作用,加快电子传输速率、导电性和稳定性,使其表现出良好的电催化性能,为潜在的电解水催化剂的开发提供了重要方法。(According to the invention, by utilizing the strong complexation effect of the antirust agent molecules 2, 4, 6-tri (amino caproyl) -1, 3, 5-triazine on metal ions and the characteristic that ammonia gas released in the heating process provides alkaline conditions, cobalt-iron hydrotalcite/carbon is prepared first, and then the cobalt sulfide/cobalt-iron hydrotalcite/nano carbon bifunctional catalyst is prepared by low-temperature vulcanization. The method avoids the harsh high-temperature condition of the organic molecule derived carbon-based catalyst, the molecular characteristics of the metal complex in the precursor solution enable the metal type nanoparticles to be uniformly dispersed on the nanocarbon carrier, the specific surface area and the active sites are increased, the contact and interaction between the metal type and the carbon material are increased, the electron transmission rate, the conductivity and the stability are accelerated, the good electrocatalytic performance is shown, and an important method is provided for the development of a potential electrolytic water catalyst.)

1. A method for preparing a bifunctional electrolytic water catalyst by using antirust agent molecules is characterized in that cobalt-iron hydrotalcite/nanocarbon is prepared by utilizing the strong complexation of the antirust agent molecules 2, 4, 6-tri (aminocaproyl) -1, 3, 5-triazine on metal ions and the characteristic of releasing ammonia gas to provide alkaline conditions in the heating process, and then vulcanization is carried out to prepare the cobalt sulfide/cobalt-iron hydrotalcite/nanocarbon bifunctional catalyst, wherein the antirust agent molecules 2, 4, 6-tri (aminocaproyl) -1, 3, 5-triazine are marked as TAAT, the cobalt-iron hydrotalcite/carbon is marked as CoFe-LDH/C, and the cobalt sulfide/cobalt-iron hydrotalcite/nanocarbon is marked as CoS_1.097The method comprises the following specific steps of:

weighing a certain amount of TAAT, and dispersing in 10mL of N, N-dimethylformamide to form a uniform milky white solution A, wherein the concentration of the TAAT is 5-34 mM; a certain amount of Fe (NO)₃)₃·9H₂O and Co (NO)₃)₂·6H₂Dissolving O in 10mL of N, N-dimethylformamide to form an orange yellow solution B, and enabling the concentration of total metal ions to be 75 mM; mixing the solution A and the solution B, magnetically stirring the mixture at room temperature for 1 hour, transferring the mixture to a polytetrafluoroethylene stainless steel high-pressure reaction kettle, and reacting the mixture at 120-200 DEG CNaturally cooling to room temperature for 8-16 h, centrifugally collecting a solid product, washing with ethanol and deionized water for three times respectively, and performing vacuum drying at 60 ℃ to obtain a dark brown solid CoFe-LDH/C; uniformly dispersing a certain amount of thioacetamide in 30mL of ethanol, adding 100-300 mg of fully ground CoFe-LDH/C powder, magnetically stirring for 30min at normal temperature, transferring to a polytetrafluoroethylene stainless steel autoclave, vulcanizing at 120-200 ℃ for 2-12 h, naturally cooling to room temperature, centrifuging to collect the obtained product, respectively washing with ethanol and deionized water for three times, and vacuum drying at 60 ℃ to obtain a black solid catalyst CoS_1.097/CoFe-LDH/C；

Fe (NO) in the above step₃)₃·9H₂O and Co (NO)₃)₂·6H₂The molar ratio of O is 1: 2; the resulting CoS_1.097CoFe-LDH in the/CoFe-LDH/C composite catalyst is an ultrathin nanosheet, and the thickness of the ultrathin nanosheet is 2-6 nm; CoS_1.097And CoFe-LDH are interwoven together and assembled on the nitrogen-doped nano carbon in a mosaic mode.

2. The method for preparing the cobalt sulfide/cobalt iron hydrotalcite-like compound/nano carbon nanosheet bifunctional electrolytic water catalyst according to claim 1, wherein the cobalt sulfide/cobalt iron hydrotalcite-like compound/nano carbon nanosheet compound obtained by the preparation method can be used for an anodic oxygen evolution reaction and a cathodic hydrogen evolution reaction of alkaline electrolytic water.

The technical field is as follows:

the invention belongs to the technical field of new energy materials and electrocatalysis, and particularly relates to a method for preparing a cobalt sulfide/ferrocobalt hydrotalcite/nanocarbon compound dual-functional electrocatalyst by a solvothermal method, and further comprises the electrocatalysis application of the catalyst in an alkaline electrolyzed water anode oxygen evolution reaction and a cathode hydrogen evolution reaction

Background art:

with the rapid development of modern industry, the demand of human beings for fossil fuels is increasing, and the environmental problems caused by the demand are attracting human attention. In recent years, researchers have been working on the development of clean energy to replace non-renewable energy sources such as oil, natural gas, and the like. Among many clean energy sources, hydrogen energy has attracted attention of researchers due to its high efficiency of energy generation and environmental friendliness. The electrolysis of water to produce hydrogen is the most economic and environmental-friendly hydrogen production strategy which is generally accepted at present. The electrolytic water reaction is divided into two half reactions: oxygen Evolution Reactions (OER) and Hydrogen Evolution Reactions (HER). Noble metal based catalyst (RuO)₂Pt/C, etc.) have better catalytic activity on OER and HER reactions. However, the noble metal-based catalyst is limited by high cost and poor stability when used for large-scale hydrogen production. Therefore, there is an urgent need to develop a highly efficient electrocatalyst with low cost and good stability.

Transition metal-based Layered Double Hydroxides (LDHs) are excellent catalysts for OER reactions due to their large specific surface area, excellent mechanical properties, and tunable electronic structure. However, the original LDHs have serious accumulation problems, which are not beneficial to the exposure of reaction active sites and the transmission and diffusion of electrolyte ions, and the ultrathin two-dimensional structure of the LDH often has structural deformation under electrochemical conditions, so that the catalytic activity of the LDH is limited. To overcome the limitations of the original LDHs, hybrid LDH-based nanostructures have been developed as potential multifunctional nanocatalysts for catalyzing OER and HER reactions. The hybridization strategy can not only induce 2D LDHs to be converted into a 3D nano structure, enlarge the specific surface area of the nano structure, improve the electrochemical stability and conductivity, but also expose more catalytic activity edge sites. These are all key factors for improving the electrochemical performance of electrolytic water.

Carbon-based catalysts show great promise as ORR/OER/HER catalysts due to the wide availability of carbon, excellent electrical conductivity, and tunable structure and physicochemical properties. Compared with non-noble metal base transition metal catalyst, it has the features of low cost, less heavy metal pollution, etc. Carbon-based catalysts represented by amorphous carbon, one-dimensional Carbon Nanotubes (CNTs), 2D graphene, and 3D graphitic carbon are often used as carriers for transition metal-based catalysts, not only enhancing the conductivity of the transition metal-based catalysts and promoting high dispersion of active sites, but also providing mechanical support for the composite catalysts. Therefore, the composite catalyst generated by the hybridization of the carbon-based catalyst and the transition metal-based catalyst shows huge electrocatalytic potential.

The invention takes ternary carboxylic acid type water-based antirust agent 2, 4, 6-tri (amino caproyl) -1, 3, 5-triazine (TAAT) as a ligand, synthesizes the cobalt sulfide/cobalt iron hydrotalcite/nano carbon composite electrocatalyst in a two-step solvothermal mode, and avoids the severe high-temperature condition to realize the compounding of the hydrotalcite-like catalyst and the carbon-based catalyst. TAAT as a water-based antirust agent has good metal ion complexing ability, and a polar group of the TAAT can firmly complex and fix iron ions in a precursor solution, so that CoFe-LDH formed in the solvothermal process is embedded into nanocarbon, and a carbon source and a nitrogen source are provided for the formation of a nitrogen-doped nanocarbon carrier. Although the cobalt ion is not complexed by TAAT, it can catalyze the conversion of TAAT to nitrogen-doped nanocarbon. In the second step, the valence state of cobalt ions is regulated through solvothermal vulcanization, and the OER and HER catalytic activities of the catalyst are further enhanced.

The invention realizes the compounding of the hydrotalcite-like nano-sheets and the nano-carbon carrier only by a simple solvothermal method, and the nano-carbon carrier provides mechanical support for the hydrotalcite-like nano-sheets, thereby improving the conductivity and stability of the composite catalyst. The molecular characteristics of the metal complex in the precursor solution are favorable for the generated CoFe-LDH nano-sheet and CoS_1.097The uniform distribution of the nanoparticles can expose more active sites. The one-step in-situ synthesis method enhances the interaction and contact area between the metal active sites and the nano carbon, and accelerates the electron transmission rate. The electrocatalyst prepared by the method fully exerts the synergistic effect of hydrotalcite-like compound and nano carbon in the aspect of electrocatalysis, and develops novel dual-function electricityThe catalyst for water splitting has important significance.

The invention content is as follows:

aiming at the harsh preparation conditions of the existing MOF derived carbon-based catalyst and the requirements of research and application in the field, one of the purposes of the invention is to provide a method for synthesizing a cobalt sulfide/ferrocobalt hydrotalcite/nano carbon bifunctional electrocatalyst, which is characterized in that the carbon-based composite catalyst is synthesized only by simple solvothermal synthesis, and the method comprises the following specific steps:

weighing a certain amount of TAAT, and dispersing in 10mL of N, N-dimethylformamide to form a uniform milky white solution A, wherein the concentration of the TAAT is 5-34 mM; a certain amount of Fe (NO)₃)₃·9H₂O and Co (NO)₃)₂·6H₂Dissolving O in 10mL of N, N-dimethylformamide to form an orange yellow solution B, and enabling the concentration of total metal ions to be 75 mM; mixing the solution A and the solution B, magnetically stirring the mixture at room temperature for 1h, transferring the mixture to a polytetrafluoroethylene stainless steel high-pressure reaction kettle, reacting the mixture at 120-200 ℃ for 8-16 h, naturally cooling the mixture to room temperature, centrifugally collecting solid products, washing the solid products with ethanol and deionized water for three times respectively, and performing vacuum drying at 60 ℃ to obtain a dark brown solid CoFe-LDH/C; uniformly dispersing a certain amount of thioacetamide in 30mL of ethanol, adding 100-300 mg of fully ground CoFe-LDH/C powder, magnetically stirring for 30min at normal temperature, transferring to a polytetrafluoroethylene stainless steel autoclave, vulcanizing at 120-200 ℃ for 2-12 h, naturally cooling to room temperature, centrifuging to collect the obtained product, respectively washing with ethanol and deionized water for three times, and vacuum drying at 60 ℃ to obtain a black solid catalyst CoS_1.097/CoFe-LDH/C；

Wherein Fe (NO)₃)₃·9H₂O and Co (NO)₃)₂·6H₂The molar ratio of O is 1: 2; the resulting CoS_1.097CoFe-LDH in the/CoFe-LDH/C composite catalyst is an ultrathin nanosheet, and the thickness of the ultrathin nanosheet is 2-6 nm; CoS_1.097And CoFe-LDH are interwoven together and assembled on the nitrogen-doped nano carbon in a mosaic mode.

The invention also aims to provide application of the cobalt sulfide/cobalt iron hydrotalcite/nano carbon dual-function electrolytic water catalyst synthesized by simple solvothermal reaction in alkaline electrolytic water anode OER and alkaline electrolytic water cathode HER.

The invention synthesizes CoFe-LDH/C in situ by one step through a simple solvothermal method by means of the complexation of a water-based antirust agent TAAT on metal ions, and synthesizes CoS through a sulfuration solvothermal method_1.097the/CoFe-LDH/C composite catalyst avoids the harsh preparation conditions of the MOF derived carbon-based catalyst, and the nano carbon carrier provides mechanical support for the hydrotalcite-like nano sheets, thereby increasing the conductivity, stability and catalytic activity of the electrolytic water reaction of the composite catalyst.

Compared with the prior art, the invention has the following main advantages and beneficial effects:

1) the bifunctional electrolytic water catalyst is a non-noble metal composite material, the used raw materials are easy to purchase and prepare, the resources are rich, the price is low, the operation is easy, and the large-scale production is facilitated;

2) the preparation method of the bifunctional electrolytic water catalyst is simple, and compared with a carbon-based catalyst derived from MOF, the bifunctional electrolytic water catalyst is prepared by simple solvothermal reaction;

3) the water electrolysis catalyst has better OER reaction activity and has remarkable advantages compared with the catalytic activity of the OER catalyst reported in the current research;

4) compared with the commercialized noble metal catalyst, the bifunctional water electrolysis catalyst provided by the invention has the advantages that the stability is obviously improved, and the good catalytic activity can be maintained in the water electrolysis process.

Description of the drawings:

FIG. 1 shows CoS obtained in example 1_1.097XRD patterns of/CoFe-LDH/C complexes and CoFe-LDH/C obtained in comparative example 1 (left), CoS obtained in example 1_1.097Transmission electron micrograph of/CoFe-LDH/C complex (right).

FIG. 2 depicts the CoS obtained in example 1_1.097OER linear voltammogram of/CoFe-LDH/C complex, CoFe-LDH/C obtained in comparative example 1, and S/Co/C modified glassy carbon electrode obtained in comparative example 2

FIG. 3 depicts the CoS obtained in example 1_1.097the/CoFe-LDH/C complex modifies a glassy carbon electrode at 10mA/cm²Is as followsTime-current curve test chart.

FIG. 4 shows the CoS obtained in example 1_1.097Nyquist curves of the/CoFe-LDH/C, CoFe-LDH/C obtained in comparative example 1, and S/Co/C complex modified glassy carbon electrode obtained in comparative example 2 in a 1M KOH solution.

FIG. 5 depicts the CoS obtained in example 1_1.097The electric double layer capacitance (C) calculated by measuring different sweep rate CV curves of a/CoFe-LDH/C, CoFe-LDH/C obtained in comparative example 1 and S/Co/C composite modified glassy carbon electrode obtained in comparative example 2 in a 1M KOH solution_dl)。

FIG. 6 depicts the CoS obtained in example 2_1.097the/CoFe-LDH/C complex, CoFe-LDH/C obtained in comparative example 1, and S/Co/C modified glassy carbon electrode obtained in comparative example 2 were measured in a 1M KOH solution to obtain HER linear voltammograms.

FIG. 7 shows the CoS obtained in example 2_1.097the/CoFe-LDH/C complex modifies a glassy carbon electrode at 10mA/cm²The time-current curve below is a test chart.

The specific implementation mode is as follows:

for a further understanding of the invention, reference will now be made to the following examples and drawings, which are not intended to limit the invention in any way.

Example 1:

80mg of TAAT (2, 4, 6-tris (aminocaproyl) -1, 3, 5-triazine) dispersed in 10mL of N, N-dimethylformamide to form a homogeneous milky white solution A, the concentration of TAAT being 17Mm, 101mg of Fe (NO)₃)₃·9H₂O and 146mg Co (NO)₃)₂·6H₂O is dissolved in 10mL of N, N-dimethylformamide to form an orange yellow solution B, Fe³⁺And Co²⁺After the solution A and the solution B are mixed, magnetically stirring for 1h at room temperature to ensure that the solution A and the solution B are uniformly mixed, transferring the mixture into a polytetrafluoroethylene stainless steel high-pressure reaction kettle, reacting for 12h at 160 ℃, naturally cooling to room temperature, centrifugally collecting a product, respectively cleaning for three times by using ethanol and deionized water, performing vacuum drying at 60 ℃ to obtain a dark brown solid, namely CoFe-LDH/C, uniformly dispersing 360mg of TAA (thioacetamide) into 30mL of ethanol, adding 150mg of fully ground brown powder CoFe-LDH/C, and magnetically stirring at the rotating speed of 600rpm at normal temperatureAfter 30min, the mixture is transferred to a polytetrafluoroethylene stainless steel autoclave and vulcanized for 6h at 160 ℃. Naturally cooling to room temperature, centrifuging to collect the obtained product, respectively cleaning with ethanol and deionized water for three times, and vacuum drying at 60 deg.C to obtain black solid, marked as CoS_1.097/CoFe-LDH/C。

Example 2:

80mg of TAAT (2, 4, 6-tris (aminocaproyl) -1, 3, 5-triazine) dispersed in 10mL of N, N-dimethylformamide to form a homogeneous milky white solution A, the concentration of TAAT being 17Mm, 101mg of Fe (NO)₃)₃·9H₂O and 146mg Co (NO)₃)₂·6H₂O is dissolved in 10mL of N, N-dimethylformamide to form an orange yellow solution B, Fe³⁺And Co²⁺After the solution A and the solution B are mixed, magnetically stirring for 1h at room temperature to ensure that the solution A and the solution B are uniformly mixed, transferring the mixture into a polytetrafluoroethylene stainless steel high-pressure reaction kettle, reacting for 12h at 160 ℃, naturally cooling to room temperature, centrifugally collecting a product, respectively cleaning for three times by using ethanol and deionized water, and performing vacuum drying at 60 ℃ to obtain a dark brown solid, namely CoFe-LDH/C, uniformly dispersing 360mg of TAA (thioacetamide) into 30mL of ethanol, adding 150mg of fully ground brown powder CoFe-LDH/C, magnetically stirring for 30min at the normal temperature at the rotating speed of 600rpm to ensure that the mixture is uniformly mixed, transferring the mixture into a polytetrafluoroethylene stainless steel autoclave, and vulcanizing for 4h at 160 ℃. Naturally cooling to room temperature, centrifuging to collect the obtained product, respectively cleaning with ethanol and deionized water for three times, and vacuum drying at 60 deg.C to obtain black solid, marked as CoS_1.097/CoFe-LDH/C。

Example 3:

118mg of TAAT (2, 4, 6-tris (aminocaproyl) -1, 3, 5-triazine) dispersed in 10mL of N, N-dimethylformamide to form a homogeneous milky white solution A, the concentration of TAAT being 25Mm, 101mg of Fe (NO)₃)₃·9H₂O and 146mg Co (NO)₃)₂·6H₂O is dissolved in 10mL of N, N-dimethylformamide to form an orange yellow solution B, Fe³⁺And Co²⁺Is 25mM and 50mM, after the solution A and the solution B are mixed, the mixture is magnetically stirred for 1 hour at room temperature, and then the mixture is transferred to polytetrafluoroethylene after being uniformly mixedReacting for 16 hours in a high-pressure reaction kettle made of ethylene stainless steel, naturally cooling to room temperature, centrifuging to collect a product, respectively cleaning with ethanol and deionized water for three times, vacuum drying at 60 ℃ to obtain a dark brown solid, marking as CoFe-LDH/C, uniformly dispersing 240 mg of TAA (thioacetamide) in 30mL of ethanol, adding 150mg of fully ground brown powder CoFe-LDH/C, magnetically stirring at the normal temperature at the rotating speed of 600rpm for 30min to uniformly mix, transferring to a polytetrafluoroethylene stainless steel autoclave, and vulcanizing for 8 hours at 120 ℃. Naturally cooling to room temperature, centrifuging to collect the obtained product, respectively cleaning with ethanol and deionized water for three times, and vacuum drying at 60 deg.C to obtain black solid, marked as CoS_1.097/CoFe-LDH/C。

Example 4:

38mg of TAAT (2, 4, 6-tris (aminocaproyl) -1, 3, 5-triazine) dispersed in 10mL of N, N-dimethylformamide to form a homogeneous milky white solution A, the concentration of TAAT being 8mM, 101mg of Fe (NO)₃)₃·9H₂O and 146mg Co (NO)₃)₂·6H₂O is dissolved in 10mL of N, N-dimethylformamide to form an orange yellow solution B, Fe³⁺And Co²⁺After the solution A and the solution B are mixed, magnetically stirring for 1 hour at room temperature to ensure that the solution A and the solution B are uniformly mixed, transferring the mixture into a polytetrafluoroethylene stainless steel high-pressure reaction kettle, reacting for 8 hours at 180 ℃, naturally cooling to room temperature, centrifugally collecting a product, respectively cleaning for three times by using ethanol and deionized water, and performing vacuum drying at 60 ℃ to obtain a dark brown solid, namely CoFe-LDH/C, wherein 480mg of TAA (thioacetamide) is uniformly dispersed in 30mL of ethanol, adding 150mg of fully ground brown powder CoFe-LDH/C, magnetically stirring for 30 minutes at the normal temperature at the rotating speed of 600rpm to ensure that the mixture is uniformly mixed, transferring the mixture into a polytetrafluoroethylene stainless steel high-pressure kettle, and vulcanizing for 3 hours at 180 ℃. Naturally cooling to room temperature, centrifuging to collect the obtained product, respectively cleaning with ethanol and deionized water for three times, and vacuum drying at 60 deg.C to obtain black solid, marked as CoS_1.097/CoFe-LDH/C。

Comparative example 1:

80mg of TAAT (2, 4, 6-tris (aminocaproyl) -1, 3, 5-triazine) dispersed in 10mL of N, N-dimethylformamide to form a homogeneous milky white solution A, of TAATAt a concentration of 17Mm, 101mg Fe (NO)₃)₃·9H₂O and 146mg Co (NO)₃)₂·6H₂O is dissolved in 10mL of N, N-dimethylformamide to form an orange yellow solution B, Fe³⁺And Co²⁺After the solution A and the solution B are mixed, magnetically stirring for 1h at room temperature, uniformly mixing, transferring to a polytetrafluoroethylene stainless steel high-pressure reaction kettle, reacting for 12h at 160 ℃, naturally cooling to room temperature, centrifugally collecting a product, respectively washing with ethanol and deionized water for three times, and performing vacuum drying at 60 ℃ to obtain a dark brown solid which is marked as CoFe-LDH/C.

Comparative example 2:

80mg of TAAT (2, 4, 6-tris (aminocaproyl) -1, 3, 5-triazine) was dispersed in 10mL of N, N-dimethylformamide to form a homogeneous milky white solution A, the concentration of TAAT being 17Mm and 146mg of Co (NO)₃)₂·6H₂O is dissolved in 10mL of N, N-dimethylformamide to form a solution B, Co²⁺The concentration of the compound is 50mM, after the solution A and the solution B are mixed, the mixture is magnetically stirred for 1h at room temperature, the mixture is transferred to a polytetrafluoroethylene stainless steel high-pressure reaction kettle after being uniformly mixed, the reaction is carried out for 12h at 160 ℃, the mixture is naturally cooled to room temperature, products are centrifugally collected, ethanol and deionized water are respectively used for cleaning for three times, vacuum drying is carried out at 60 ℃ to obtain purple solid, the purple solid is marked as Co/C,360mg of TAA (thioacetamide) is uniformly dispersed in 30mL of ethanol, 150mg of fully ground purple powder is added, the mixture is magnetically stirred for 30min at the normal temperature at the rotating speed of 600rpm and is transferred to a polytetrafluoroethylene stainless steel high-pressure kettle after being uniformly mixed, and vulcanization is carried out for 6h at 160 ℃. And naturally cooling to room temperature, centrifuging and collecting the obtained product, respectively cleaning the product with ethanol and deionized water for three times, and performing vacuum drying at 60 ℃ to obtain a black solid which is recorded as S/Co/C.

FIG. 1 left shows the CoS obtained in example 1_1.097XRD patterns of/CoFe-LDH/C complex and CoFe-LDH/C obtained in comparative example 1. As shown, CoS_1.097LDH characteristic peaks appear for both/CoFe-LDH/C and CoFe-LDH/C, indicating that CoFe-LDH maintains good crystal characteristics in both complexes. But CoS after vulcanization_1.097Appearance of CoS in the/CoFe-LDH/C Complex_1.097Characteristic diffraction peak of (1), indicating Co formationS_1.097，CoS_1.097Is an active center of OER reaction, and can enhance OER activity. FIG. 1 right shows the CoS obtained in example 1_1.097Transmission electron micrograph of/CoFe-LDH/C complex. As shown in the figure, the vulcanized ferrocobalt hydrotalcite nanosheets are successfully loaded on the nanocarbon, so that superimposed areas with different depths can be obviously observed, the light color part is a nanocarbon carrier, the dark color part shows the vulcanized ferrocobalt hydrotalcite nanosheets, and the white dotted line area shows that the boundary between the nanocarbon and the hydrotalcite and the cobalt sulfide is clear. Meanwhile, the high-power transmission crystal lattice has clear stripes and respectively corresponds to a (102) crystal face, a (108) crystal face and CoS of the LDH_1.097Crystal plane (306) and crystal plane (330) of (1). This is consistent with XRD results. The cobalt sulfide/cobalt iron hydrotalcite nano-sheet is successfully loaded on the nano-carbon through a high-resolution transmission electron microscope.

Example 5:

respectively dispersing 10mg of the catalysts obtained in the example 1, the comparative example 1 and the comparative example 2 in 300 mu L of ethanol and 30 mu L of 0.5 percent Nafion solution, ultrasonically mixing the solutions, dripping 6 mu L of slurry on a glassy carbon electrode, and measuring the OER electro-catalytic performance of the glassy carbon electrode on a CHI660D electrochemical workstation after the glassy carbon electrode is completely dried;

the electrocatalysis performance tests all use a saturated Ag/AgCl electrode as a reference electrode, a carbon rod as a counter electrode, the sweep rate is 5mV/s, and the electrolyte is 1M KOH.

Example 6:

respectively dispersing 10mg of the catalysts obtained in the example 1, the comparative example 1 and the comparative example 2 in 300 mu L of ethanol and 30 mu L of 0.5% Nafion solution, ultrasonically mixing the solutions, dripping 6 mu L of slurry on a glassy carbon electrode, and measuring the HER electrocatalytic performance of the glassy carbon electrode on a CHI660D electrochemical workstation after the glassy carbon electrode is completely dried;

the electrocatalysis performance tests all use a saturated Ag/AgCl electrode as a reference electrode, a carbon rod as a counter electrode, the sweep rate is 5mV/s, and the electrolyte is 1M KOH.

FIG. 2 depicts the CoS obtained in example 1_1.097OER linear voltammograms of the/CoFe-LDH/C complex, CoFe-LDH/C obtained in comparative example 1, and S/Co/C modified glassy carbon electrode obtained in comparative example 2. As shown in the figure, when the current density is 10mA/cm²Of CoS_1.097The overpotentials for the/CoFe-LDH/C, CoFe-LDH/C and S/Co/C were about 168, 277 and 401mV, respectively. It is clearly seen that after sulfidation and addition of Fe, the overpotential is greatly reduced, mainly because the active center cobalt sulfide that forms OER after sulfidation and the addition of Fe can also increase its OER activity.

FIG. 3 depicts the CoS obtained in example 1_1.097the/CoFe-LDH/C complex modifies a glassy carbon electrode at 10mA/cm²The time-current curve below is a test chart. As shown, CoS was obtained through a continuous OER process of 15h_1.097The OER current density of/CoFe-LDH/C has no obvious attenuation, thus showing that CoS_1.097the/CoFe-LDH/C modified electrode shows good OER catalytic stability in an alkaline solution and has a long service life.

FIG. 4 shows the CoS obtained in example 1_1.097Nyquist curves of the/CoFe-LDH/C, CoFe-LDH/C obtained in comparative example 1, and S/Co/C complex-modified glassy carbon electrode obtained in comparative example 2 in a 1M KOH solution (see inset for an equivalent circuit diagram). At a test voltage of 1.40V, the charge transfer resistance of S/Co/C is about 28 Ω, while the charge transfer resistance of CoFe-LDH/C is about 13 Ω, and the charge transfer resistance is greatly reduced after the addition of Fe. And CoS_1.097The charge transport capacity of the/CoFe-LDH/C is about 5 omega, and the charge transport efficiency is further improved after vulcanization.

FIG. 5 depicts the CoS obtained in example 1_1.097The electric double layer capacitance (C) calculated by measuring CV curves of different sweep rates in a 1M KOH solution for the/CoFe-LDH/C, the CoFe-LDH/C obtained in the comparative example 1 and the S/Co/C composite modified glassy carbon electrode obtained in the comparative example 2_dl). The electrochemical active area (ECSA) is an important parameter for evaluating the intrinsic activity of the catalyst, ECSA and C_dlIs in direct proportion. S/Co/C, CoFe-LDH/C and CoS_1.097C of/CoFe-LDH/C_dlAre respectively 14.7mF cm^-2，20.5mF·cm^-2And 44.9mF cm^-2. After the introduction of Fe and sulfidation, the active sites of the catalyst are exposed to varying degrees, which is more favorable for the conversion of reaction intermediates to oxygen at the catalyst surface.

FIG. 6 depicts the CoS obtained in example 2_1.097CoFe-LDH/C complexes, comparativeThe linear voltammogram of HER was measured in a 1M KOH solution for CoFe-LDH/C obtained in example 1 and for S/Co/C modified glassy carbon electrode obtained in comparative example 2. As shown in the figure, when the current density is 10mA/cm²Of CoS_1.097The overpotentials for the/CoFe-LDH/C, CoFe-LDH/C and S/Co/C were about 283, 372, and 412mV, respectively. It can be seen that the catalyst has HER activity after sulfidation. Fe, although not the active center of HER, is critical for the structure formation of the catalyst.

FIG. 7 shows the CoS obtained in example 2_1.097the/CoFe-LDH/C complex modifies a glassy carbon electrode at 10mA/cm²The time-current curve below is a test chart. As shown, CoS, a continuous HER process over 15h_1.097No significant decrease in HER current density was observed for the/CoFe-LDH/C, from which CoS was seen_1.097the/CoFe-LDH/C modified electrode shows good HER catalytic stability in an alkaline solution and has longer service life.