Ultra-small-size ruthenium-rhenium-oxygen solid solution particle electrocatalyst and preparation method thereof

Abstract

The invention discloses an ultra-small-size ruthenium-rhenium-oxygen solid solution particle water electrolysis catalyst and a preparation method thereof. Ruthenium-rhenium alloy grows on the surface of rhenium trioxide through a solvothermal method to obtain a ruthenium-rhenium-oxygen solid solution, XPS characterization proves that the product contains multivalent ruthenium and rhenium components and a rhenium trioxide carrier, the particle size of ruthenium-rhenium nanoparticles on the carrier is 1-3 nm, and the utilization rate of ruthenium is greatly increased. An electrochemical test shows that the mass activity, the stability and the cost performance of the catalyst in a pure seawater electrolytic reaction are higher than those of commercial platinum. The catalyst has great significance on commercialization of a direct seawater electrolysis hydrogen production technology.

Description

Technical Field

[0001] This invention belongs to the field of preparation of water electrolysis catalysts and application of water electrolysis technology, specifically relating to an ultra-small size ruthenium-rhenium-oxygen solid solution particle electrocatalyst and its preparation method. Background Technology

[0002] Hydrogen production through water electrolysis is a promising method, offering renewable raw materials and electricity, and producing high-purity products. However, its widespread adoption may face challenges related to high energy consumption and freshwater resource depletion. Seawater electrolysis, which fully utilizes offshore wind and solar power and the virtually unlimited supply of raw water, represents a promising application path for reducing the cost of water electrolysis. While phosphorus (Pt) is currently the best-performing catalyst for hydrogen evolution, its high cost and scarcity limit the large-scale application of seawater electrolysis technology. Furthermore, the complex ionic environment in seawater poses a significant challenge to the stable operation of the catalyst. Compared to Pt, Ru is a cheaper precious metal and also possesses some hydrogen evolution activity, thus having the potential to replace Pt. However, Ru faces two major challenges in seawater hydrogen evolution reactions: difficulties in hydrolysis and dehydrogenation.

[0003] Re is the cheapest of the precious metals and is stable. Studies have found that alloying Re with Pt can improve Pt's hydrolysis ability. Furthermore, research indicates that Re and its oxides can anchor small-sized metal particles, which not only improves the utilization rate of active metals but also increases the oxidation level on the alloy particle surface. This facilitates hydrogen atom desorption, thereby enhancing the hydrogen evolution performance of the active metal.

[0004] In summary, we designed a ruthenium-rhenium-oxygen solid solution particle with ReO3 as the support, in which ruthenium-rhenium alloy particles are grown on the ReO3 surface. The ruthenium-rhenium alloy particles have an ultra-small particle size and a rich variety of oxidation states. They exhibit excellent activity and stability in the hydrogen evolution reaction in seawater and greatly reduce the amount of precious metals used, showing potential to replace commercial Pt catalysts. Summary of the Invention

[0005] The purpose of this invention is to provide an ultra-small size ruthenium-rhenium-oxygen solid solution particle electrocatalyst.

[0006] An ultra-small ruthenium-rhenium-oxygen solid solution particle electrocatalyst, wherein the electrocatalyst has a solid solution structure, the metal components include ruthenium (Ru) and rhenium (Re), and the support is rhenium trioxide (ReO3), with the chemical formula Ru. x Re 1-x / ReO3, where 0.5 ≤ x ≤ 0.8.

[0007] The Ru x Re 1-x The particle size is 1-3 nm, preferably about 2 nm. Ru x Re1-x The loading is 5.0-10.0 wt%, preferably 6.37 wt%.

[0008] In some preferred embodiments, the molecular formula of the ultra-small ruthenium-rhenium-oxygen solid solution particle electrocatalyst is Ru. 0.6 Re 0.4 / ReO3. Particle size 2±0.2nm.

[0009] In the XRD pattern, the electrocatalyst shows that 38.4°, 42.2°, and 44.0° correspond to the hexagonal crystal planes of Ru, and 37.6°, 40.5°, and 42.9° correspond to the hexagonal crystal planes of Re. TEM images show numerous 1-3 nm particles grown on the surface of the rhenium trioxide (ReO3) support. XPS characterization reveals that the catalyst contains both metallic and oxidized states, indicating a ruthenium-rhenium-oxygen solid solution.

[0010] The present invention also aims to provide a method for preparing an ultra-small ruthenium-rhenium-oxygen solid solution particle electrocatalyst, comprising the following steps: S1: Disperse ReO3 in an organic solvent to obtain a suspension; S2: Add a mixed solution of ruthenium salt and rhenium salt to the suspension, and add a morphology modifier; S3: A solvothermal reaction is carried out to obtain the precursor precipitate; S4: After washing and drying the precipitate, heat treatment is carried out in a reducing atmosphere to obtain the electrocatalyst.

[0011] In step S1, the organic solvent is selected from C1-C5 alcohol solutions.

[0012] The ruthenium salt mentioned in step S2 is any one of ruthenium chloride, anhydrous ruthenium chloride, and ruthenium nitrate; the rhenium salt is any one of ammonium perrhenate, rhenium oxide, and sodium perrhenate; the molar ratio of ruthenium to rhenium in the ruthenium salt and the rhenium salt is 6:4 to 8:2.

[0013] The morphology modifier mentioned in step S2 is any one of tetramethylammonium bromide, ethyltrimethylammonium bromide, tetrabutylphosphine chloride, diethylenetriamine-ammonium acetate, and sodium pyrophosphate.

[0014] The solvothermal reaction in step S3 is carried out under microwave assistance at a temperature of 150-180°C for 1-3 hours.

[0015] The heat treatment in step S4 is carried out in a hydrogen-containing inert atmosphere. First, it is kept at 150-180℃ for 1-2 hours, and then heated to 210-250℃ for calcination for 2-4 hours. The amount of hydrogen used is 1-10% of the volume of the inert atmosphere, and the inert atmosphere is selected from argon or nitrogen.

[0016] In some preferred embodiments, the preparation method of the ultra-small ruthenium-rhenium-oxygen solid solution particle electrocatalyst includes the following steps: S1: Prepare a solution by dispersing ReO3 in an alcohol solvent; S2: Add ruthenium chloride and ammonium perrhenate pre-complexed in a 6:4 molar ratio to the suspension, add a morphology modifier, and heat at 100 °C for 14 h.

[0017] S3: The resulting mixture was transferred to a polytetrafluoroethylene-lined reactor and subjected to microwave-assisted solvothermal reaction at 160°C for 2 h to obtain a precipitate. S4: After washing and vacuum drying the precipitate, it was first kept at 180 °C for 1 h in a 5% H2 / N2 atmosphere, and then calcined at 210 °C for 3 h to obtain Ru with a particle size of about 2 nm. 0.6 Re 0.4 / ReO3 solid solution electrocatalyst.

[0018] Another objective of this invention is to provide an application of an ultra-small ruthenium-rhenium alloy oxide electrocatalyst for hydrogen production via seawater electrolysis.

[0019] The present invention also provides a method for producing hydrogen by seawater electrolysis, using the aforementioned electrocatalyst as a hydrogen evolution catalyst, with an electrolysis temperature of 20~30℃ and the electrolyte being natural seawater or simulated seawater.

[0020] Compared with the prior art, the beneficial effects of the present invention are: (1) This invention is the first to prepare ruthenium-rhenium-oxygen solid solution particulate electrocatalyst with ReO3 as support and a particle size of only 1-3 nm by solvothermal method.

[0021] (2) By introducing rhenium components, ReO3 support, and combining microwave solvothermal method and surfactant, the present invention reduces the size of solid solution particles, thereby increasing the number of active sites on the catalyst surface.

[0022] (3) The electrocatalyst prepared by the present invention has a large number of rhenium sites and abundant metal oxidation states, which together accelerate the hydrogen evolution reaction on the catalyst surface. Compared with graphene-supported ruthenium-rhenium particles and graphene-supported ruthenium particles, the current density of ruthenium-rhenium oxygen solid solution particles is increased by about 3 times and more than 10 times at an overpotential of 0.1 V.

[0023] (4) When the electrocatalyst prepared in this invention is applied to the hydrogen evolution reaction of seawater electrolysis, the electrocatalyst is used as the working electrode, the carbon rod is used as the counter electrode, and Hg / HgO is used as the reference electrode. The hydrogen evolution reaction is tested in pure seawater at 25°C. The results show that its current density is 2 times and 3 times that of commercial Pt / C and commercial Ru / C, respectively, and its mass activity is more than 6 times that of them.

[0024] (5) The electrocatalyst prepared in this invention can effectively resist chloride ion corrosion in the electrolysis of seawater hydrogen evolution reaction and can operate stably for more than 100 h. Attached Figure Description

[0025] The accompanying drawings, which constitute a part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a TEM image of Example 1.

[0026] Figure 2 This is the EDS element distribution diagram of Example 1.

[0027] Figure 3 These are XRD comparison images of Examples 1, 2, 3, and 4.

[0028] Figure 4 This is the XPS spectrum of Example 1.

[0029] Figure 5 These are the current polarization curves of Example 1, commercial Ru / C, and Pt / C.

[0030] Figure 6 These are the timing current curves for Example 1, and commercial Ru / C and Pt / C. Detailed Implementation

[0031] The following specific descriptions are exemplary and intended to provide further explanation of the present invention. Those skilled in the art should understand that modifications or substitutions to the details and form of the technical solutions of the present invention can be made without departing from the spirit and scope of the invention, but all such modifications and substitutions fall within the protection scope of the present invention.

[0032] Unless otherwise specified, the experimental methods used in the following experimental examples are all conventional methods.

[0033] Example 1: Ru 0.6 Re 0.4 Synthesis of ReO3 ultra-small size ruthenium-rhenium-oxygen solid solution particle electrocatalyst A 0.1 mol / mL ruthenium chloride solution and a 0.1 mol / mL ammonium perrhenate solution were prepared separately. A 10 mg / mL solution of ReO3 was prepared by dispersing it in ethanol. A bimetallic precursor solution pre-complexed from 6 mL of ruthenium chloride and 4 mL of ammonium perrhenate was added to 5 mL of the suspension, along with diethylenetriamine-ammonium acetate as a morphology modifier. The mixture was heated at 100 °C for 14 h. The resulting mixture was transferred to a polytetrafluoroethylene-lined reactor and subjected to a microwave-assisted solvothermal reaction at 160 °C for 2 h to obtain a precipitate. The precipitate was washed, vacuum dried, and then calcined at 180 °C for 1 h in a 5% H2 / N2 atmosphere, followed by calcination at 210 °C for 3 h to obtain Ru with a particle size of 2 nm. 0.6 Re 0.4 / ReO3 solid solution electrocatalyst.

[0034] Example 2: Ru 0.5 Re 0.5 Synthesis of O / ReO3 solid solution particulate electrocatalyst The specific implementation conditions are similar to those in Example 1, but 5 mL of ruthenium chloride solution and 5 mL of ammonium perrhenate are added to the suspension. Ru is obtained. 0.5 Re 0.5 O / ReO3 solid solution particulate electrocatalyst.

[0035] Example 3: Ru 0.8 Re 0.2 Synthesis of O / ReO3 solid solution particulate electrocatalyst The specific implementation conditions are similar to those in Example 1, but 8 mL of ruthenium chloride solution and 2 mL of ammonium perrhenate are added to the suspension. Ru is obtained. 0.8 Re 0.2 O / ReO3 solid solution particulate electrocatalyst.

[0036] Example 4: Ru 0.7 Re 0.3 Synthesis of O / ReO3 solid solution particulate electrocatalyst The specific implementation conditions are similar to those in Example 1, but 7 mL of ruthenium chloride solution and 3 mL of ammonium perrhenate are added to the suspension. Ru is obtained. 0.7 Re 0.3 O / ReO3 solid solution particulate electrocatalyst.

[0037] Example 5 The specific implementation conditions are similar to those in Example 1, but the morphology control agent is selected from tetrabutylphosphine chloride, resulting in Ru 0.6 Re 0.4 / ReO3 solid solution electrocatalyst-1.

[0038] Example 6 The specific implementation conditions are similar to those in Example 1, but the morphology control agent is selected from sodium citrate, resulting in Ru. 0.6 Re 0.4 / ReO3 solid solution electrocatalyst-2.

[0039] Comparative Example 1: Graphene loaded with Ru 0.6 Re 0.4 Synthesis of nanoparticles The specific implementation conditions are similar to those in Example 1, but the carrier is graphene.

[0040] Comparative Example 2: Synthesis of Ru Nanoparticles The specific implementation conditions are similar to those in Example 1, with graphene as the carrier and only 10 mL of ruthenium chloride added, resulting in a Ru / C product.

[0041] Figure 1 It is the Ru prepared in Example 1 0.6 Re 0.4 TEM analysis of the ReO3 electrocatalyst revealed that the catalyst nanoparticle size is approximately 2 nm, with numerous alloy particles distributed on the bulk ReO3 support.

[0042] Figure 2 The EDS elemental distribution spectrum of Example 1 shows that Ru, Re, and O are present in the catalyst and are evenly distributed. In the support portion, the distribution of Re and O is more concentrated, while Ru is more dispersed and has lower brightness because it exists only in the alloy particles. The EDS spectrum confirms that the catalyst is a ruthenium-rhenium-oxygen solid solution, and that the RuRe alloy particles are distributed around the ReO3 support.

[0043] Figure 3 These are the XRD patterns of Examples 1, 2, 3, and 4. All examples show strong Ru and Re diffraction peaks. The Ru diffraction peaks are at 38.4°, 42.2°, and 44.0°, and the Re diffraction peaks are at 37.6°, 40.5°, and 42.9°.

[0044] Figure 4 The results show that all examples contain Ru and Re in metallic and oxidized states, and some ruthenium-rhenium alloy oxide nanoparticles contain lattice oxygen, further proving that the nanoparticles are oxygen-containing solid solutions.

[0045] To demonstrate the beneficial effects of this invention, ruthenium-rhenium-oxygen solid solution particles prepared in Example 1 were used as a catalyst and drop-coated onto the working electrode (area: A three-electrode system was formed, consisting of hydrophobic carbon paper, a reference electrode Hg / HgO, and a counter electrode graphite rod. The system was used to test ruthenium-rhenium oxide solid solution particles prepared in Example 1, commercial Pt / C, and graphene-supported Ru in a nitrogen-saturated pure seawater solution.0.6 Re 0.4 Hydrogen evolution (HER) polarization curves were measured using a three-electrode system on a CHI1140D electrochemical workstation. The test voltage range was -0.3 V to 0.1 V, and the scan rate was 10 mV / s. All measurement potentials were converted to a reversible hydrogen electrode. The linear sweep voltammetry (LSV) curves (relative to RHE) of the ruthenium-rhenium-oxygen solid solution particles prepared in Example 1 and commercial Pt / C as catalysts in pure seawater are shown below. Figure 5 .

[0046] Stability testing was performed using chronopotential analysis with a current density of 20 mA / cm². -2 The test duration was 30 h to 170 h, and the chronopotential curves are shown below. Figure 6 The three curves are arranged in the following order: the top curve corresponds to Ru / C, the middle curve corresponds to Pt / C, and the bottom curve corresponds to Ru. 0.6 Re 0.4 / ReO3.

[0047] Depend on Figure 5 It can be seen that the Ru prepared in Example 1 0.6 Re 0.4 / ReO3 electrocatalyst at 10mA / cm -2 At the specified current density, the overpotential is only 172.4 mV, significantly lower than the 246.4 mV of commercial Pt / C catalysts and the 417.4 mA of graphene-supported Ru. Furthermore, Ru... 0.6 Re 0.4 The ReO3 electrocatalyst can operate stably for over 170 hours, while the performance of Pt / C is almost zero after 110 hours. Therefore, the ruthenium-rhenium-oxygen solid solution particulate electrocatalyst has potential commercial value.

[0048] Under the above detection conditions, the obtained Ru 0.5 Re 0.5 O / ReO3 solid solution particulate electrocatalyst, Ru 0.8 Re 0.2 O / ReO3 solid solution particulate electrocatalyst, Ru 0.7 Re 0.3 O / ReO3 solid solution particulate electrocatalyst, Ru 0.6 Re 0.4 / ReO3 solid solution electrocatalyst-1, Ru 0.6 Re 0.4 / ReO3 solid solution electrocatalyst-2, graphene-supported Ru 0.6 Re 0.4 Nanoparticles, graphene-supported Ru particles (Ru / C).

[0049] .

[0050] The above description is not intended to limit the present invention, nor is the present invention limited to the examples given above. Any changes, modifications, additions, or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A small-sized ruthenium-rhenium-oxygen solid solution particle electrocatalyst, characterized in that, The electrocatalyst has a solid solution structure, with metal components including ruthenium (Ru) and rhenium (Re), and the support is rhenium trioxide (ReO3) with the chemical formula Ru. x Re 1-x / ReO3, where 0.5 ≤ x ≤ 0.

8.

2. The electrocatalyst according to claim 1, characterized in that, The Ru x Re 1-x The particle size is 1-3 nm.

3. The electrocatalyst according to claim 1, characterized in that, In the XRD pattern, approximately 38°, 42°, and 44° correspond to the hexagonal crystal planes of Ru, and approximately 37.5°, 40.5°, and 43° correspond to the hexagonal crystal planes of Re. The catalyst contains both metallic and oxidized states and is a ruthenium-rhenium-oxygen solid solution.

4. The electrocatalyst according to claim 1, characterized in that, Ru x Re 1-x The load capacity is 5.0-10.0 wt%.

5. A method for preparing an electrocatalyst as described in any one of claims 1 to 4, characterized in that, Includes the following steps: S1: Disperse ReO3 in an organic solvent to obtain a suspension; S2: Add a mixed solution of ruthenium salt and rhenium salt to the suspension, and add a morphology modifier; S3: A solvothermal reaction is carried out to obtain the precursor precipitate; S4: After washing and drying the precipitate, heat treatment is carried out in a reducing atmosphere to obtain the electrocatalyst.

6. The preparation method according to claim 5, characterized in that, The ruthenium salt mentioned in step S2 is any one of ruthenium chloride, anhydrous ruthenium chloride, and ruthenium nitrate; The rhenium salt is any one of ammonium perrhenate, rhenium oxide, or sodium perrhenate; The molar ratio of ruthenium to rhenium in ruthenium and rhenium salts is 6:4 to 8:

2.

7. The preparation method according to claim 5, characterized in that, The morphology modifier mentioned in step S2 is any one of tetramethylammonium bromide, ethyltrimethylammonium bromide, tetrabutylphosphine chloride, diethylenetriamine-ammonium acetate, and sodium pyrophosphate.

8. The preparation method according to claim 7, characterized in that, The solvothermal reaction in step S3 is carried out under microwave assistance at a temperature of 150-180°C for 1-3 hours.

9. The preparation method according to claim 8, characterized in that, The heat treatment in step S4 is carried out in a hydrogen-containing inert atmosphere. First, it is held at 150-180℃ for 1-2 hours, and then heated to 210-250℃ for calcination for 2-4 hours. The amount of hydrogen used is 1-10% of the volume of the inert atmosphere, and the inert atmosphere is selected from argon or nitrogen.

10. A method for producing hydrogen by seawater electrolysis, characterized in that, The electrocatalyst as described in any one of claims 1 to 5 is used as the hydrogen evolution catalyst, the electrolysis temperature is 20 to 30°C, and the electrolyte is natural seawater or simulated seawater.

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