Synthesis and application of Pt-based MOFs electro-catalytic material

Abstract

The invention relates to synthesis and application of a Pt-based MOFs (Metal-Organic Frameworks) electro-catalytic material. Pt nano particles contained in the material are formed by reducing potassium chloroplatinate on synthesized modified UIO-66 containing Co single atoms, and the Co single atoms are anchored by a porphyrin organic ligand with a metal center and calcined to prepare the carbon-based electrocatalyst. The porphyrin organic ligand adopted by the invention is 5, 10, 15, 20-tetra (4-carboxylphenyl) cobalt porphyrin (CoTCPP) which is doped into MOF (UIO-66) to serve as a precursor for preparing the electrocatalyst, and the preparation process is mature and suitable for commercial production. In order to obtain a high-performance hydrogen evolution reaction (HER), an in-situ strategy is adopted to jointly embed Pt nano particles and Co single atoms into an N-doped carbon material to obtain the composite electro-catalytic material (Pt at Co-NC), so that the composite electro-catalytic material has respective advantages and even a synergistic effect, the performance of the composite electro-catalytic material can be comparable to that of commercial Pt / C in the aspect of electro-catalytic hydrogen evolution, and the composite electro-catalytic material is suitable for industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of electrocatalytic hydrogen evolution, and in particular to the synthesis and application of a Pt-based MOFs electrocatalytic material. Background Art

[0002] Energy is an essential material foundation for human survival and development, and a focal point of contemporary international political, economic, and military diplomacy. Sustained and rapid economic and social development cannot be achieved without a strong energy guarantee. As we all know, hydrogen energy has the advantages of very high energy density, renewability, and being pollution-free. The purity of hydrogen produced by water electrolysis can reach over 99%, making it an important method for industrial hydrogen production. Converting electrical energy into relatively stable chemical energy, while producing hydrogen without producing other byproducts, is an environmentally friendly and important method for achieving sustainable hydrogen storage. However, due to the sluggish kinetics of the hydrogen evolution reaction (HER), water electrolysis has low efficiency and high energy consumption. Therefore, developing highly active and durable electrocatalysts is essential to accelerate these reactions and thus improve energy conversion efficiency. Research on catalytic materials is of great significance to electrocatalytic hydrogen production technology.

[0003] Metal-organic frameworks (MOFs) are materials composed of ordered assemblies of metal nodes and organic ligands. They possess exceptional surface area and functional tunability and are considered important precursors for the pyrolysis-derived carbon-based materials supporting metal species. Crucially, various organic ligands containing heteroatoms serve as excellent attachment sites for individual metal atoms. In particular, effective chemical bonds between metal atoms and heteroatoms allow for the anchoring of metal atoms, minimizing migration and aggregation during pyrolysis. The catalytic performance of electrocatalysts is generally determined by two factors: the number of catalytically active sites and the intrinsic activity of individual sites. Recent studies have demonstrated that reducing catalyst particle size can increase the number of catalytically active sites and expose more active surface area, while enhancing the intrinsic properties of metal sites by tailoring their electronic structure. Reducing catalyst particles to the atomic level provides an effective approach for maximizing metal atom utilization and improving the intrinsic catalytic activity of catalysts. In this regard, single-atom catalysts have attracted considerable attention in recent years due to their larger geometric and electrochemical surface areas, more exposed active sites, and greater utilization efficiency and low cost compared to bulk and nanoparticles. However, as far as we know, the quality activity of precious metal catalysts currently used in the field of electrocatalytic hydrogen evolution is generally not high, which increases production costs.

[0004] Therefore, synthesizing a Pt-based MOFs electrocatalytic material and using it for electrocatalytic hydrogen evolution research is the research direction of those skilled in the art. Summary of the Invention

[0005] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to synthesize a Pt-based MOFs electrocatalytic material to solve the problems in the prior art of expensive, small storage capacity, and difficulty in industrial use of precious metal-based catalytic materials.

[0006] The present invention also provides a method for preparing a Pt-based MOFs electrocatalytic material, and the composite electrocatalytic material can be prepared by the method.

[0007] The present invention also provides an application of a Pt-based MOFs electrocatalytic material. The composite electrocatalytic material prepared by the preparation method of the present invention is suitable for electrocatalytic hydrogen evolution reaction under acidic conditions.

[0008] The technical solution adopted in the present invention is as follows:

[0009] A method for preparing a Pt-based MOFs electrocatalytic material comprises the following steps:

[0010] Step 1) Using ZrCl4, terephthalic acid, benzoic acid and tetracarboxyphenylporphyrin cobalt as raw materials, the intermediate CoTCPP@UIO-66 is prepared by a hydrothermal method;

[0011] Step 2) The intermediate CoTCPP@UIO-66, potassium chloroplatinate, and sodium borohydride are stirred in deionized water to obtain the precursor Pt@CoTCPP@UIO-66;

[0012] Step 3) The precursor Pt@CoTCPP@UIO-66 is placed in a tubular furnace and calcined to generate a composite electrocatalyst Pt@Co-NC.

[0013] Wherein, in said step 1), the reaction temperature is 130 degrees and the reaction time is 12 hours;

[0014] In the step 2), the reduction reaction time is 30 min;

[0015] In the step 3), the calcination temperature is 800 degrees and the time is 2 hours;

[0016] The present invention also provides an application of a Pt-based MOFs electrocatalytic material, characterized in that the Pt nanoparticle-coordinated Co single-atom bimetallic electrocatalytic material is prepared by the method described in claim 1; the Pt nanoparticle-coordinated Co single-atom bimetallic electrocatalytic material is suitable for electrocatalytic hydrogen evolution applications under acidic conditions and exhibits excellent effects.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] 1. The preparation method of the Pt nanoparticle-Co single-atom bimetallic electrocatalytic material provided by the present invention enables the obtained composite electrocatalytic material Pt@Co-NC to maintain the morphology of Pt@CoTCPP@UIO-66 before calcination and fully expose the active sites; the addition of CoTCPP provides single-atom sites Co on the one hand, and the pyrrole N in the porphyrin structure and single atoms anchor the metal Pt nanoparticles on the other hand, forming a special composite structure of single-atom-anchored nanoparticles.

[0019] 2. The Pt nanoparticles and Co single-atom bimetallic electrocatalytic material prepared by the present invention are suitable for electrocatalytic hydrogen evolution research under acidic conditions and show excellent hydrogen evolution effect and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the XRD pattern of UIO-66 prepared in Example 1.

[0021] Figure 2 This is the SEM image of UIO-66 prepared in Example 1.

[0022] Figure 3 This is the XRD pattern of CoTCPP@UIO-66 prepared in Example 2.

[0023] Figure 4 This is the SEM image of CoTCPP@UIO-66 prepared in Example 2.

[0024] Figure 5 XRD pattern of Co-NC prepared in Example 3.

[0025] Figure 6 This is the SEM image of Co-NC prepared in Example 3.

[0026] Figure 7 Figure 3 shows the electrocatalytic hydrogen evolution of Co-NC prepared in Example 3.

[0027] Figure 8 SEM image of Pt@Co-NC prepared in Example 4.

[0028] Figure 9 This is the XRD pattern of Pt@Co-NC prepared in Example 4.

[0029] Figure 10 Electrocatalytic hydrogen evolution diagram of Pt@Co-NC prepared in Example 4.

[0030] Figure 11 This is the electrocatalytic impedance diagram of Pt@Co-NC prepared in Example 4. DETAILED DESCRIPTION

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] Example 1:

[0033] The preparation method of UIO-66 material comprises the following steps:

[0034] (1) ZrCl4 (0.39 mg), terephthalic acid (0.277 g), and benzoic acid (6 g) were added to 20 mL of DMF and stirred for 30 minutes to fully dissolve the raw materials. The mixture was then placed in a reactor and reacted at 130°C for 12 hours. After the reaction was cooled, the solid was centrifuged and washed several times with DMF and ethanol, and finally dried to obtain UIO-66.

[0035] from Figure 1 The XRD pattern shows that UIO-66 was successfully synthesized. Figure 2 The SEM image shows that the morphology of the prepared UIO-66 presents an octahedral structure.

[0036] Example 2:

[0037] The preparation method of CoTCPP@UIO-66 material includes the following steps:

[0038] (1) ZrCl4 (0.39 mg), terephthalic acid (0.277 g), benzoic acid (6 g), and CoTCPP (12 mg) were added to 20 mL of DMF and stirred for 30 minutes to fully dissolve the raw materials. The mixture was then placed in a reactor and reacted at 130°C for 12 hours. After the reaction was cooled, the solid was centrifuged and washed several times with DMF and ethanol, and finally dried to obtain CoTCPP@UIO-66.

[0039] from Figure 3 The XRD pattern of CoTCPP@UIO-66 reflects the crystal information of CoTCPP@UIO-66 generated after calcination. Figure 4 The SEM image shows that the morphology of the prepared CoTCPP@UIO-66 presents an octahedral structure.

[0040] Example 3:

[0041] The preparation method of Co-NC material comprises the following steps:

[0042] (1) ZrCl4 (0.39 mg), terephthalic acid (0.277 g), benzoic acid (6 g), and CoTCPP (12 mg) were added to 20 mL of DMF and stirred for 30 minutes to fully dissolve the raw materials. The mixture was then placed in a reactor and reacted at 130°C for 12 hours. After the reaction was cooled, the solid was centrifuged and washed several times with DMF and ethanol before drying to obtain CoTCPP@UIO-66.

[0043] (2) 200 mg of CoTCPP@UIO-66 was calcined at 800 °C for 2 h under circulating N2 to obtain Co-NC; Figure 5 The XRD pattern of the Co-NC crystals after calcination reflects the information. Figure 6 The SEM images show that the morphology of the prepared Co-NC presents an octahedral structure;

[0044] The prepared Co-NC material was used in electrocatalytic hydrogen evolution as follows:

[0045] (1) Preparation of the test electrode: Weigh 1 mg of Co-NC material and add it to 490 μL of ethanol / water solution (volume ratio of 1:1), add 10 μL of Nafion solution, and then ultrasonicate for 30 minutes to evenly disperse the catalytic material; take 4 μL of the mixed solution after ultrasonication and drop it onto the glassy carbon electrode, let it dry naturally and then set aside.

[0046] (2) Electrocatalytic hydrogen evolution test: A three-electrode test mode was selected, with the reference electrode being a saturated calomel electrode, the counter electrode being a carbon rod electrode, the working electrode being a glassy carbon electrode loaded with catalytic material, and the acidic electrolyte being 0.5 M H2SO4.

[0047] Attachment Figure 7 This is the result of electrocatalytic hydrogen evolution of the prepared Co-NC material.

[0048] Example 4:

[0049] The preparation method of Pt@Co-NC material includes the following steps:

[0050] (1) ZrCl4 (0.39 mg), terephthalic acid (0.277 g), benzoic acid (6 g), and CoTCPP (12 mg) were added to 20 mL of DMF and stirred for 30 minutes to fully dissolve the raw materials. The mixture was then placed in a reactor and reacted at 130°C for 12 hours. After the reaction was cooled, the solid was centrifuged and washed several times with DMF and ethanol, and finally dried to obtain CoTCPP@UIO-66.

[0051] (2) The obtained CoTCPP@UIO-66 was reduced with 0.1 mol potassium chloroplatinate in a solution containing sodium borohydride for 30 min;

[0052] (3) 200 mg of Pt@CoTCPP@UIO-66 was calcined at 800 °C for 2 h under circulating N2 conditions to obtain Pt@Co-NC.

[0053] from Figure 8 The SEM image shows that the morphology of the prepared Pt@Co-NC presents an octahedral structure. Figure 9The XRD pattern of Pt@Co-NC reflects the crystal information of Pt@Co-NC generated after calcination, which proves the existence of Pt nanoparticles.

[0054] The prepared Pt@Co-NC material was used in electrocatalytic hydrogen evolution as follows:

[0055] (1) Preparation of the test electrode: Weigh 1 mg of Pt@Co-NC material and add it to 490 μL of ethanol / water solution (volume ratio of 1:1). Add 10 μL of Nafion solution and then ultrasonicate for 30 minutes to evenly disperse the catalytic material. Take 4 μL of the ultrasonicated mixed solution and drop it onto the glassy carbon electrode. Allow it to dry naturally before use.

[0056] (2) Electrocatalytic hydrogen evolution test: A three-electrode test mode was selected, with the reference electrode being a saturated calomel electrode, the counter electrode being a carbon rod electrode, the working electrode being a glassy carbon electrode loaded with catalytic material, and the acidic electrolyte being 0.5 M H2SO4.

[0057] Attachment Figure 10 and Figure 11 This is the result of electrocatalytic hydrogen evolution of the prepared Pt@Co-NC material. Its hydrogen evolution effect is comparable to that of commercial Pt / C.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the technical solutions. Those skilled in the art should understand that modifications or equivalent replacements of the technical solutions of the present invention that do not depart from the purpose and scope of the technical solutions of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A Pt-based MOFs electrocatalytic material synthesized using an in-situ strategy, characterized in that: The electrocatalytic material is a composite electrocatalytic material Pt@Co-NC.

2. A method for preparing a Pt-based MOFs electrocatalytic material, characterized in that: The preparation of the Pt nanoparticle and Co single-atom electrocatalytic material as claimed in claim 1 comprises the following steps: Step 1) Using ZrCl4, terephthalic acid, benzoic acid and tetracarboxyphenylporphyrin Co as raw materials, the intermediate CoTCPP@UIO-66 is prepared by a hydrothermal method; Step 2) The intermediate CoTCPP@UIO-66, potassium chloroplatinate, and sodium borohydride are stirred in deionized water to obtain the precursor Pt@CoTCPP@UIO-66; Step 3) The precursor Pt@CoTCPP@UIO-66 is placed in a tubular furnace and calcined to generate a composite electrocatalyst Pt@Co-NC.

3. The method for preparing the Pt-based MOFs electrocatalytic material according to claim 2, characterized in that: In step 1), the molar ratio of ZrCl4, terephthalic acid, benzoic acid and CoTCPP is 1:1:20:0.

05.

4. The method for preparing the Pt-based MOFs electrocatalytic material according to claim 2, characterized in that: In step 1), the raw materials are added to an organic solvent DMF, and after the raw materials are fully dissolved, they are placed in a reactor and reacted at 130° C. for 12 hours.

5. The method for preparing the Pt-based MOFs electrocatalytic material according to claim 2, characterized in that: In step 2), 0.1 mol of chloroplatinic acid was added, and the reduction reaction time was 30 min.

6. The method for preparing the Pt-based MOFs electrocatalytic material according to claim 2, characterized in that: In step 3), the calcination temperature is 800° C. and the calcination time is 2 h.

7. An application of a Pt-based MOFs electrocatalytic material, characterized in that: The Pt nanoparticle-coordinated Co single-atom bimetallic electrocatalytic material prepared by the preparation method according to any one of claims 2 to 6 is suitable for electrocatalytic hydrogen evolution reaction under acidic conditions.

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