Application of titanium carbide supported osmium metal catalyst for hydrogen and deuterium isotope separation by electrolysis of water

Abstract

The application discloses application of a titanium carbide loaded osmium metal hydrogen evolution and deuterium evolution catalyst in water electrolysis separation of hydrogen isotopes, the carrier of the hydrogen evolution and deuterium evolution catalyst is titanium carbide, the active component is osmium metal loaded on the carrier, and the loading amount of the osmium metal is 7-15% of the mass of the carrier. The hydrogen isotope separation efficiency is improved by improving the composition and structure of the hydrogen evolution and deuterium evolution catalyst. The osmium metal is loaded on the titanium carbide base, the hydrogen evolution selectivity is improved and the energy consumption is reduced through strong mutual action of the metal-carrier.

Description

Technical Field

[0001] This invention relates to the field of electrocatalysis technology, and in particular to the application of a titanium carbide-supported osmium metal hydrogen evolution and deuteration catalyst in the electrolysis of water to separate hydrogen isotopes. Background Technology

[0002] Electrolysis of heavy water requires high-purity heavy water, making heavy water enrichment crucial. Industrially common enrichment methods include the hydrogen sulfide two-temperature exchange method and the two-temperature ammonia-hydrogen exchange method, both of which require processing large quantities of flammable, corrosive, and toxic fluids. In contrast, electrolysis is a promising approach for purifying heavy water. The core of this method is utilizing the kinetic difference between the hydrogen evolution reaction (HER) and the deuterium evolution reaction (DER) to selectively remove water from the system. The isotope separation efficiency of the catalyst is mainly determined by the hydrogen-deuterium separation factor (α). H / D (Evaluate)

[0003] Commercial platinum-carbon (Pt / C) catalysts exhibit low hydrogen evolution overpotentials in both acidic and alkaline media, and are therefore often referred to as benchmark catalysts for hydrogen isotope separation (HER). However, they suffer from high cost and relatively low hydrogen isotope separation efficiency. Therefore, designing and developing hydrogen isotope separation catalysts with high separation efficiency has become a key step in the research. Summary of the Invention

[0004] To address the aforementioned technical problems in existing technologies, the present invention aims to provide an application of a titanium carbide-supported osmium metal hydrogen evolution and deuteration catalyst in the electrolysis of water to separate hydrogen isotopes. This invention selects osmium metal, also a platinum group metal, as the catalyst material, which is less expensive than platinum metal. The charge distribution of the osmium metal nanoparticles is controlled through strong metal-support interaction (SMSI), thereby improving the hydrogen isotope separation efficiency of the catalyst.

[0005] The technical solution adopted in this invention is as follows:

[0006] An application of a titanium carbide-supported osmium metal hydrogen evolution and deuteration catalyst in the electrolysis of water to separate hydrogen isotopes. The catalyst is supported on titanium carbide, and the active component is osmium metal supported on the support. The loading amount of osmium metal is 7-15% of the support mass.

[0007] The preparation method of the hydrogen evolution and deuterium evolution catalyst includes the following steps:

[0008] S1: Weigh out osmium salt, dissolve it in a solvent, add titanium carbide, and mix thoroughly;

[0009] S2: The mixture obtained in step S1 is placed in an oven to dry, so that the solvent is completely evaporated, and then naturally cooled to room temperature to obtain the mixture powder;

[0010] S3: The powder mixture from step S2 is placed in a ceramic boat and then transferred to a tube furnace for firing. First, an inert gas is introduced to purge the air, and then a hydrogen-inert gas mixture is continuously introduced. The osmium salt is reduced under heating and then naturally cooled to room temperature to obtain the catalyst.

[0011] Further, in step S1, the osmium salt includes at least one of osmium trichloride (OsCl3), osmium acetylacetonate (OsCl3), potassium hexachloroosmiumate (K2OsCl6), or ammonium hexachloroosmiumate (NH4)2OsCl6; in step S1, the mass ratio of osmium metal element to titanium carbide in the osmium salt is 0.07 to 0.15:1.

[0012] Further, in step S1, the solvent includes at least one of ethanol and water, and the volume of the solvent used is 3-5 μL / mg based on the mass of titanium carbide.

[0013] Furthermore, in step S2, the drying temperature range of the oven is 100~140 ℃, and the drying time is 1~2 hours.

[0014] Further, in step S3, the inert gas includes at least one of nitrogen or argon, and the volume ratio of hydrogen to the inert gas in the mixed gas is 0.8 to 1:1; in step S3, the calcination temperature is 300 to 450 °C, and the holding time is 3 to 5 hours.

[0015] In the application described in this invention, a membrane electrode system is used to electrolyze a hydrogen isotope-containing electrolyte.

[0016] The membrane electrode system includes a membrane electrode and conductive support materials attached to both sides thereon.

[0017] The membrane electrode is based on an anion exchange membrane, with the titanium carbide-supported osmium metal hydrogen and deuterium evolution catalyst loaded on the cathode side of the anion exchange membrane and the oxygen evolution catalyst loaded on the anode side.

[0018] Furthermore, the hydrogen evolution and deuterium evolution catalyst loading on the cathode side of the anion exchange membrane is 0.5 mg / cm³. 2 ~5 mg / cm 2 Preferably 1.5-2 mg / cm 2 The oxygen evolution catalyst loading on the anode side of the anion exchange membrane is 0.5 mg / cm³. 2 ~5 mg / cm 2 Preferably 1.5-2 mg / cm 2 The oxygen evolution catalyst is IrO2.

[0019] Furthermore, the electrolysis temperature is 0–10 °C, and the electrolysis current density is 0.5–1.5 A / cm³. 2 .

[0020] Furthermore, the hydrogen isotope electrolyte contains the electrolyte NaOD, with a NaOD concentration of 0.5-4 mol / L.

[0021] In a specific embodiment of the present invention, when conducting an electrolysis experiment, a NaOD heavy water-light water mixed solution with a deuterium atom abundance of 90% is electrolyzed. Due to the selective hydrogen evolution of the catalyst, the light water is consumed preferentially, thereby achieving the purpose of enriching the heavy water.

[0022] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0023] (1) This invention provides a novel titanium carbide-supported osmium metal hydrogen evolution and deuterium evolution catalyst, which improves the hydrogen isotope separation efficiency by improving the composition and structure of the hydrogen evolution and deuterium evolution catalyst. Osmium metal is supported on a titanium carbide substrate, and hydrogen evolution selectivity is improved and energy consumption is reduced by SMSI.

[0024] (2) When the hydrogen evolution and deuterium evolution catalyst of the present invention is applied, it not only has a high separation efficiency, but also the cost of the hydrogen evolution and deuterium evolution catalyst is lower than that of Pt / C, thus improving economic benefits.

[0025] (3) The application of the hydrogen evolution and deuterium evolution catalyst of the present invention effectively improves the economic efficiency of the heavy water enrichment process, reduces pollution emissions and energy consumption losses in the production process, and promotes the application and development of electrocatalysis technology in other engineering and industrial fields. Attached Figure Description

[0026] Figure 1 This is a TEM image of the titanium carbide-supported osmium metal catalyst for hydrogen and deuterium evolution in Example 1.

[0027] Figure 2 Separation factor α for electrocatalytic reactions of titanium carbide-supported osmium hydrogen evolution and deuterium evolution catalysts and platinum-carbon (Pt / C) catalysts at 0 °C under different preparation conditions. H / D ;

[0028] Figure 3 Separation factor α of titanium carbide-supported osmium metal catalysts for hydrogen and deuterium evolution under different temperature conditions H / D . Detailed Implementation

[0029] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0030] Separation factor: Represents the degree to which a particular separation operation or process separates two substances, typically denoted by α. In the process of separating hydrogen isotopes through water electrolysis, the separation factor α is defined as:

[0031] ;

[0032] In the formula "This indicates the molar ratio of H to D in the generated gas." "" indicates the molar ratio of H / D in the solution before electrolysis.

[0033] AEM electrolysis of water: AEM is an abbreviation for Anion Exchange Membrane. AEM electrolysis of water involves the decomposition of water molecules under a specific voltage, first through the catalytic action of a cathode catalyst, to produce hydrogen gas and hydroxide ions (OH-). - ), then OH - Hydrogen and water are generated by passing through an anion exchange membrane under the catalysis of the anolyte catalyst. Because the hydrogen produced at the cathode and the oxygen produced at the anode are effectively separated by the anion exchange membrane, the hydrogen produced by this method has a high purity.

[0034] In this embodiment of the invention, titanium carbide (TiC, 98%, particle size 60 nm) was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., boron carbide (B4C, 98%, particle size 60 nm) was purchased from Beasley New Materials Co., Ltd., acetylene black (99.9%, 50% compression ratio) was purchased from Thermo Technologies Co., Ltd., and commercial platinum carbon (SPT-10) was purchased from Suzhou Shengerno Co., Ltd. The mass fraction of Pt in commercial platinum carbon (SPT-10) was 10%.

[0035] Example 1: Preparation of a titanium carbide-supported osmium metal electrocatalyst:

[0036] First, 18.5 mg of OsCl3 was dissolved completely in 400 μL of anhydrous ethanol by ultrasonication. Then, it was added to a ceramic crucible along with 100 mg of titanium carbide and stirred thoroughly. The crucible was then dried in a 120 °C oven for 1 h, followed by natural cooling to room temperature. The resulting catalyst powder was ground and transferred to a ceramic boat, which was then placed in a tube furnace. Air was first purged with nitrogen for 30 min, followed by annealing with a 1:1 hydrogen-nitrogen mixture (both at a flow rate of 60 mL / min). The furnace temperature was increased from room temperature to 350 °C at a rate of 5 °C / min and held at this temperature for 3 h. After the process, the temperature was allowed to cool naturally to obtain the final hydrogen and deuterium evolution catalyst.

[0037] TEM image of the hydrogen evolution and deuterium evolution catalyst in Example 1 is shown below. Figure 1 ,from Figure 1 It can be seen that the osmium nanoparticles were successfully loaded onto the titanium carbide support and were distributed relatively evenly.

[0038] Example 2: The preparation steps of the hydrogen evolution and deuterium evolution catalyst in Example 2 are the same as those in Example 1, except that the amount of OsCl3 is replaced with 13.0 mg, and the other conditions remain unchanged.

[0039] Example 3: The preparation steps of the hydrogen evolution and deuterium evolution catalyst in Example 3 are the same as those in Example 1, except that "the volume ratio of hydrogen to nitrogen is 0.8:1 and the total flow rate is kept at 120 mL / min", and the other conditions remain unchanged.

[0040] Example 4: The preparation steps of the hydrogen evolution and deuterium evolution catalyst in Example 4 are the same as those in Example 1, except that the annealing temperature is controlled at 400 °C, and the other conditions remain unchanged.

[0041] Example 5: The preparation steps of the hydrogen evolution and deuterium evolution catalyst in Example 5 are the same as those in Example 1, except that the holding time at 350°C is 4 hours, and the other conditions remain unchanged.

[0042] Comparative Example 1: The preparation steps of the hydrogen evolution and deuterium evolution catalyst in Comparative Example 1 were the same as those in Example 1, except that the volume ratio of hydrogen to nitrogen was 1:3 and the total flow rate was kept at 120 mL / min. All other conditions remained unchanged.

[0043] Comparative Example 2: The preparation steps of the hydrogen evolution and deuterium evolution catalyst in Comparative Example 2 were the same as those in Example 1, except that the amount of OsCl3 was replaced with 1.6 mg, and all other conditions remained the same.

[0044] Comparative Example 3: Comparative Example 3 only replaced titanium carbide with boron carbide of the same mass, and the rest of the steps were the same as in Application Example 1.

[0045] Comparative Example 4: Comparative Example 4 only replaced titanium carbide with an equal mass of acetylene black, and the remaining steps were the same as in Application Example 1.

[0046] Application Example 1: The hydrogen isotope separation performance of the hydrogen evolution and deuterium evolution catalysts of Examples 1-5, Comparative Examples 1-4, and commercial platinum-carbon was tested respectively.

[0047] Hydrogen evolution and deuterium evolution catalyst slurries were prepared using the hydrogen evolution and deuterium evolution catalysts of Examples 1-5, Comparative Examples 1-4, and commercial platinum-carbon, respectively: 4.0 mg of catalyst, 960 μL of a mixed solution of deionized water and isopropanol in a volume ratio of 1:3 were taken and ultrasonically dispersed for 30 min to ensure uniform dispersion. Then, 40 μL of DuPont 5 wt.% Nafion solution was added, and the mixture was ultrasonically dispersed for another 30 min to obtain the cathode catalyst slurry.

[0048] Take 4.0 mg of IrO2 catalyst, 960 μL of a mixed solution of deionized water and isopropanol in a volume ratio of 2:1, and sonicate for 30 min to disperse it evenly. Then add 40 μL of DuPont 5 wt.% Nafion solution and sonicate for another 30 min to obtain the anode catalyst slurry.

[0049] Two catalyst slurries were separately sprayed onto both sides of a Fumasep FAA-3 anion exchange membrane using an ultrasonic spraying machine to prepare membrane electrodes. The IrO2 loading on the anode side of the membrane electrode was 1.5 mg / cm³. 2 The cathode side of the membrane electrode was loaded with hydrogen evolution and deuterium evolution catalysts from Examples 1-5 and Comparative Examples 1-4, respectively, with a loading of 2 mg / cm³. 2 .

[0050] Sodium deuterium oxide (NaOD) heavy water solution is prepared using heavy water and metallic Na. A heavy water-light water mixture with a deuterium atom abundance of 90% (final NaOD concentration of 1 mol / L) is prepared using 4 mol / L NaOD solution, heavy water, and ultrapure water (H₂O) as raw materials. Conductive support materials are attached to both sides of the membrane electrode to form a membrane electrode assembly. This assembly is then placed in an anion exchange membrane (AEM) electrolytic cell. The conductive support material on the cathode side is carbon paper, and the conductive support material on the anode side is nickel fiber felt. The outer sides of the carbon paper and nickel fiber felt are in contact with the metal plates of the electrolytic cell. The metal plates on both sides of the electrolytic cell are connected to a power source via wires, and flow channels for electrolyte circulation are provided on the metal plates. The prepared NaOD heavy water-light water mixed electrolyte is introduced into the anode and cathode chambers, respectively. The electrolysis temperatures are set at 0℃, 10℃, 20℃, and 40℃, and the membrane electrode current density is controlled at 1.4 A / cm². 2 After the electrolysis stabilized, the hydrogen isotope content of the cathode gas products was detected to obtain the separation factor α at different temperatures.

[0051] Following the experimental procedure described above, the cathode catalysts selected were the hydrogen and deuterium evolution catalysts of Examples 1-5, the hydrogen and deuterium evolution catalysts of Comparative Examples 1-4, and commercial platinum-carbon, respectively. The electrolysis temperature was set to 0 °C, and the membrane electrode current density was controlled at 1.4 A / cm². 2 Separation factor α under different catalysts after electrocatalytic stabilization H / D The comparison results are shown below. Figure 2 .

[0052] Following the experimental procedure described above, when the cathode catalyst was selected as the hydrogen and deuterium evolution catalyst of Example 1, and the electrolysis temperatures were set to 0°C, 10°C, 20°C, and 40°C, the membrane electrode current density was controlled at 1.4 A / cm². 2 Separation factor α at different electrolysis temperatures after electrocatalytic stabilization H / D The results are as follows Figure 3 As shown.

[0053] The contents described in this specification are merely an enumeration of the implementation forms of the inventive concept, and the scope of protection of this invention should not be regarded as limited to the specific forms described in the embodiments.

Claims

1. An application of a titanium carbide-supported osmium metal hydrogen evolution and deuteration catalyst in the electrolysis of water to separate hydrogen isotopes, characterized in that, The catalyst for hydrogen evolution and deuterium evolution is supported on titanium carbide, and the active component is osmium metal supported on the support, with the loading of osmium metal being 7-15% of the support mass. The preparation method of the hydrogen evolution and deuterium evolution catalyst includes the following steps: S1: Weigh out osmium salt, dissolve it in a solvent, add titanium carbide, and mix thoroughly; S2: The mixture obtained in step S1 is placed in an oven to dry, so that the solvent is completely evaporated, and then naturally cooled to room temperature to obtain the mixture powder; S3: The powder mixture from step S2 is placed in a ceramic boat and then transferred to a tube furnace for firing. First, an inert gas is introduced to purge the air, and then a hydrogen-inert gas mixture is continuously introduced. The osmium salt is reduced under heating and then naturally cooled to room temperature to obtain the catalyst. In step S3, the inert gas includes at least one of nitrogen or argon, and the volume ratio of hydrogen to the inert gas in the mixed gas is 0.8 to 1:

1.

2. The application as described in claim 1, characterized in that, In step S1, the osmium salt includes at least one of osmium trichloride (OsCl3), osmium acetylacetonate (OsCl3), potassium hexachloroosmium (K2OsCl6), or ammonium hexachloroosmium (NH4)2OsCl6; in step S1, the mass ratio of osmium metal element to titanium carbide in the osmium salt is 0.07 to 0.15:

1.

3. The application as described in claim 1, characterized in that, In step S1, the solvent includes at least one of ethanol and water, and the volume of the solvent used is 3-5 μL / mg based on the mass of titanium carbide.

4. The application as described in claim 1, characterized in that, In step S2, the drying temperature range of the oven is 100~140℃, and the drying time is 1~2 hours.

5. The application as described in claim 1, characterized in that, In step S3, the calcination temperature is 300~450 ℃, and the holding time is 3~5 hours.

6. The application as described in claim 1, characterized in that, In this application, a membrane electrode system is used to electrolyze a hydrogen isotope-containing electrolyte. The membrane electrode system includes a membrane electrode and conductive support materials attached to both sides thereon. The membrane electrode is based on an anion exchange membrane, with the titanium carbide-supported osmium metal hydrogen and deuterium evolution catalyst loaded on the cathode side of the anion exchange membrane and the oxygen evolution catalyst loaded on the anode side.

7. The application as described in claim 6, characterized in that, The hydrogen and deuterium evolution catalyst loading on the cathode side of the anion exchange membrane is 0.5 mg / cm³. 2 ~5 mg / cm 2 The oxygen evolution catalyst loading on the anode side of the anion exchange membrane is 0.5 mg / cm³. 2 ~5mg / cm 2 The oxygen evolution catalyst is IrO2.

8. The application as described in claim 6, characterized in that, The electrolysis temperature is 0–10 °C, and the electrolysis current density is 0.5–1.5 A / cm³. 2 .

9. The application as described in claim 6, characterized in that, The hydrogen isotope electrolyte contains the electrolyte NaOD, with a NaOD concentration of 0.5-4 mol / L.

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