Ruthenium-nickel co-doped titanium oxide-based nanoparticle catalyst as well as preparation method and application thereof

Abstract

The invention relates to the technical field of catalysts, in particular to a ruthenium-nickel co-doped titanium oxide-based nanoparticle catalyst as well as a preparation method and application thereof. The preparation method comprises the following steps: (1) dissolving and dipping, namely stirring ruthenium chloride, nickel chloride and titanium oxide serving as precursors and deionized water serving as a solvent at 50-80 DEG C for 6-8 hours until the precursors are dried by distillation to obtain a solid intermediate product 1; (2) grinding: mixing the solid intermediate product 1 with sodium hypophosphite monohydrate, and grinding to obtain a solid intermediate product 2; and (3) annealing: heating the solid intermediate product 2 in an Ar / H2 mixed gas at 500-800 DEG C for 2-4 hours, and naturally cooling to obtain the product. The two-step synthesis method is adopted, the raw material atom utilization rate is close to 100%, no organic reagent is used in the reaction process, the method is green and safe, the reaction level is the gram level, the potential of amplification reaction is achieved, the precious metal content is only 2.5%, and the cost of the catalyst is greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and in particular to a ruthenium-nickel co-doped titanium oxide-based nanoparticle catalyst and a preparation method and application thereof. Background Art

[0002] Hydrogen production by water electrolysis is considered one of the most promising clean energy technologies due to its zero carbon emission characteristics. Proton exchange membrane water electrolysis (PEMWE) technology has attracted widespread attention due to its adaptability to fluctuating renewable energy, compact structure, and high safety. However, the anodic oxygen evolution reaction (OER) under acidic conditions requires the use of iridium oxide (IrO 2 ), ruthenium oxide (RuO 2 ) and other precious metals as catalyst substrates, and their high cost has severely restricted their large-scale application. Anion exchange membrane electrolysis of water (AEMWE) technology has shown significant advantages over PEMWE in large-scale hydrogen production scenarios: 1. Similar fast start-stop capabilities, and can also adapt to fluctuating energy sources; 2. OER under alkaline conditions can use non-precious metal-based nickel-iron catalysts, which greatly reduces material costs; 3. AEM diaphragm abandons the highly toxic fluorination process of Nafion membrane of PEM, adopts a low-toxic aromatic polymer route, and the corrosion rate of components under alkaline conditions is low, and the operation and maintenance cost is significantly better than the strongly acidic PEM system. However, the industrial development of AEM technology is still limited by two major bottlenecks: 1. The activity and durability of cathode hydrogen evolution reaction (HER) catalysts are insufficient. Existing non-precious metal catalysts (such as Ni-based materials) have slow reaction kinetics in alkaline media and are easily degraded due to surface oxidation or dissolution. The long-term stability of non-precious metal catalysts such as transition metal sulfides or phosphides is still difficult to meet industrial needs; 2. The synergistic effect of carriers and catalysts has not been fully explored: traditional carriers (such as carbon materials) are easily corroded under alkaline high potentials, resulting in the agglomeration and inactivation of active nanoparticles, which limits the service life of the catalyst.

[0003] In recent years, ruthenium (Ru)-based materials have been regarded as a potential alternative to Pt-based catalysts due to their advantages such as HER activity close to that of Pt, relatively abundant reserves, and controllable costs. However, Ru is easily covered with active sites due to surface over-oxidation or hydroxyl adsorption in alkaline environments, and nanoparticles are easily agglomerated and inactivated, limiting their practical applications. Currently, research on HER catalysts in AEMWE systems is mostly focused on single metal or alloy design, with insufficient attention paid to multi-metal synergistic doping and oxide carrier composite strategies, and there is no systematic solution for optimizing the stability of ruthenium-based materials in alkaline environments. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention aims to develop a ruthenium-nickel co-doped titanium oxide-based (Ru-Ni / TiO 2) nanoparticle catalyst, optimizing hydrogen adsorption energy through the electronic synergistic effect of Ru and Ni, TiO 2 The carrier improves structural stability and oxygen vacancies promote water dissociation, which is expected to break through the technical bottleneck of efficient, stable and low-cost HER catalysts in AEMWE. This design achieves high activity and high durability while reducing dependence on precious metals by regulating the electronic and geometric structures of active sites in multiple dimensions, providing key material support for the large-scale preparation of green hydrogen.

[0005] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0006] In one aspect, a method for preparing a ruthenium-nickel co-doped titanium oxide-based nanoparticle catalyst is provided, comprising the following steps:

[0007] (1) Dissolution impregnation: using ruthenium chloride, nickel chloride, titanium oxide as precursors and deionized water as solvent, stirring at 50-80° C. for 6-8 hours until evaporated to dryness, to obtain a solid intermediate product 1;

[0008] (2) Grinding: The solid intermediate product 1 is mixed with sodium hypophosphite monohydrate and then ground to obtain a solid intermediate product 2;

[0009] (3) Annealing: The solid intermediate product 2 is annealed in Ar / H 2 Heat at 500-800°C for 2-4 hours under mixed gas, cool naturally, and obtain the product.

[0010] Furthermore, in step (1), the mass ratio of ruthenium chloride, nickel chloride and titanium oxide is (2-5): (10-20): (50-100).

[0011] Furthermore, in step (2), the mass ratio of the solid intermediate product 1 to sodium hypophosphite monohydrate is 5:1 to 1:1.

[0012] Further, in step (3), Ar / H 2 H in the mixed gas 2 The concentration is between 2% and 5%.

[0013] On the other hand, the invention provides the use of ruthenium-nickel co-doped titanium oxide-based nanoparticle catalyst in alkaline water electrolysis hydrogen evolution reaction.

[0014] The beneficial effects of the present invention are:

[0015] 1. The present invention adopts a two-step synthesis method, using precursor salts of ruthenium and nickel metals as metal sources, and doping them into a titanium dioxide carrier by impregnation. The raw material atomic utilization rate is close to 100%, and no organic reagents are used in the reaction process. It is green and safe, the reaction level is at the gram level, and it has the potential for amplified reactions. In addition, the precious metal content is only 2.5%, which greatly reduces the cost of the catalyst.

[0016] 2. The present invention can adjust the electronic structure of Ru and optimize the adsorption free energy of hydrogen intermediate (H*) by introducing electron-donating doping metal Ni, thereby improving the intrinsic activity.

[0017] 3. The present invention uses high stability oxide TiO 2 The construction of nanocomposites for the support can not only increase the specific surface area through morphology engineering to expose more active sites, but also inhibit particle agglomeration and dissolution by using strong metal-support interaction (SMSI), solving the problem of low durability and stability of Ru under alkaline conditions. In addition, doping-induced oxygen vacancies or structural defects can promote the dissociation process of water, further accelerating the alkaline HER kinetics. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a scanning electron microscope (SEM) photograph of the ruthenium-nickel co-doped titanium oxide-based nanoparticle catalyst prepared in Example 1 of the present invention;

[0019] Figure 2 This is a scanning electron microscope (SEM) photograph of the ruthenium-nickel co-doped titanium oxide-based nanoparticle catalyst prepared in Example 2 of the present invention;

[0020] Figure 3 This is a scanning electron microscope (SEM) photograph of the ruthenium-nickel co-doped titanium oxide-based nanoparticle catalyst prepared in Example 3 of the present invention;

[0021] Figure 4 X-ray diffraction (XRD) patterns of the ruthenium-nickel co-doped titanium oxide-based nanoparticle catalysts and commercial titanium oxide prepared in Examples 2, 5, and 6 of the present invention;

[0022] Figure 5 X-ray diffraction (XRD) patterns of the ruthenium-nickel co-doped titanium oxide-based nanoparticle catalysts and commercial titanium oxide prepared in Examples 1, 3, and 4 of the present invention;

[0023] Figure 6 The hydrogen evolution polarization curves of the ruthenium-nickel co-doped titanium oxide-based nanoparticle catalysts prepared in Examples 1, 2, 3, 4, 5, and 6 of the present invention and commercial Pt / C in 1M KOH solution;

[0024] Figure 7 The ruthenium-nickel co-doped titanium oxide-based nanoparticle catalyst prepared in Example 1 of the present invention and commercial Pt / C were tested in 1M KOH solution at 10 mA / cm 2 Chronopotentiometry curves under current density conditions;

[0025] Figure 8This is an energy dispersive spectroscopy (EDS) spectrum of the ruthenium-nickel co-doped titanium oxide-based nanoparticle catalyst prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0026] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0027] Example 1

[0028] In a 50 ml beaker, 80 mg of ruthenium chloride, 400 mg of nickel chloride, 1 g of titanium oxide, and 20 ml of deionized water were added in sequence, and evaporated to dryness under magnetic stirring at 70°C to obtain solid intermediate product 1. 100 mg of solid intermediate product 1 was mixed with 20 mg of sodium hypophosphite monohydrate and ground in an agate mortar to obtain solid intermediate product 2. Solid intermediate product 2 was placed in a porcelain boat and heated under Ar / H 2 The mixture was heated at 500° C. for 2 hours and cooled naturally to obtain a product (ruthenium and nickel co-doped titanium oxide-based nanoparticle catalyst).

[0029] The morphology of the product prepared in this example was systematically studied using SEM and XRD. Figure 1 ) are characterized as nanoparticles with a particle size of 100 to 200 nm. The XRD spectrum is similar to that of TiO 2 correspond( Figure 5 ).

[0030] The product prepared in this example was compared with a commercial Pt / C catalyst. The electrochemical test was carried out in a three-electrode electrolytic cell at room temperature. The reference electrode was a mercury oxide electrode (Hg / HgO), the counter electrode was a graphite rod electrode, and the electrolyte was a 1M KOH solution prepared with ultrapure water. The product was mixed with activated carbon (Vulcan XC-72) at a mass ratio of 10:1 to obtain Ink. The glassy carbon electrode coated with Ink was subjected to a linear sweep voltammetry (LSV) test on a workstation, and then 0.5-1.5 mg of Ink was drop-coated on a 0.5-1.5 cm 2 Chronopotentiometry (CP) test was performed on carbon paper. LSV curve ( Figure 6 ) shows that at 10mA / cm 2 The overpotential was as low as 37 mV under the condition of current density. Figure 7 It shows that at 10mA / cm 2 It exhibits stability of more than 300 hours under current density conditions, which is better than commercial Pt / C.

[0031] From the EDS spectrum ( Figure 8 ) Analysis and calculation showed that the mass fractions of Ru, Ni and P in the product were 2.5%, 7% and 0.5%, respectively, and the precious metal content was only 1 / 8 of that in commercial Pt / C.

[0032] Example 2

[0033] In a 50 ml beaker, 20 mg of ruthenium chloride, 100 mg of nickel chloride, 1 g of titanium oxide, and 20 ml of deionized water were added in sequence, and evaporated to dryness under magnetic stirring at 70°C to obtain solid intermediate product 1. 100 mg of solid intermediate product 1 was mixed with 20 mg of sodium hypophosphite monohydrate and ground in an agate mortar to obtain solid intermediate product 2. Solid intermediate product 2 was placed in a porcelain boat and heated under Ar / H 2 The mixture was heated at 500° C. for 2 hours and cooled naturally to obtain a product (ruthenium and nickel co-doped titanium oxide-based nanoparticle catalyst).

[0034] The morphology of the product prepared in this example was systematically studied using SEM and XRD. Figure 2 ) are characterized as nanoparticles with a particle size of 50 to 100 nm. XRD patterns and TiO 2 correspond( Figure 4 ). LSV curve ( Figure 6 ) shows that at 10mA / cm 2 Under the condition of current density, it exhibits an overpotential of 75mV, which is on par with commercial Pt / C.

[0035] Example 3

[0036] In a 50 ml beaker, 80 mg of ruthenium chloride, 400 mg of nickel chloride, 1 g of titanium oxide, and 20 ml of deionized water were added in sequence, and evaporated to dryness under magnetic stirring at 70°C to obtain solid intermediate product 1. 100 mg of solid intermediate product 1 was mixed with 20 mg of sodium hypophosphite monohydrate and ground in an agate mortar to obtain solid intermediate product 2. Solid intermediate product 2 was placed in a porcelain boat and heated under Ar / H 2 The mixture was heated at 650° C. for 2 hours and cooled naturally to obtain a product (ruthenium-nickel co-doped titanium oxide-based nanoparticle catalyst).

[0037] The morphology of the product prepared in this example was systematically studied using SEM and XRD. Figure 3 ) are characterized as nanoparticles with a particle size of 50 to 100 nm. XRD patterns and TiO 2 correspond( Figure 5 ). LSV curve ( Figure 6 ) shows that at 10mA / cm 2 It exhibits an overpotential of 54 mV under current density conditions, which is better than commercial Pt / C.

[0038] Example 4

[0039] In a 50 ml beaker, 80 mg of ruthenium chloride, 400 mg of nickel chloride, 1 g of titanium oxide, and 20 ml of deionized water were added in sequence and evaporated to dryness under magnetic stirring at 70°C to obtain solid intermediate product 1. 100 mg of solid intermediate product 1 was mixed with 20 mg of sodium hypophosphite monohydrate and ground in an agate mortar to obtain solid intermediate product 2. Solid intermediate product 2 was placed in a porcelain boat and heated under Ar / H 2 The mixture was heated at 800° C. for 2 hours and cooled naturally to obtain a product (ruthenium and nickel co-doped titanium oxide-based nanoparticle catalyst).

[0040] XRD was used to systematically study the morphology of the product prepared in this example. 2 correspond( Figure 5 ). LSV curve ( Figure 6 ) shows that at 10mA / cm 2 It exhibits an overpotential of 110 mV under current density conditions, which is slightly lower than commercial Pt / C.

[0041] Example 5

[0042] In a 50 ml beaker, 20 mg of ruthenium chloride, 100 mg of nickel chloride, 1 g of titanium oxide, and 20 ml of deionized water were added in sequence and evaporated to dryness under magnetic stirring at 70°C to obtain solid intermediate product 1. 100 mg of solid intermediate product 1 was mixed with 20 mg of sodium hypophosphite monohydrate and ground in an agate mortar to obtain solid intermediate product 2. Solid intermediate product 2 was placed in a porcelain boat and heated under Ar / H 2 The mixture was heated at 650° C. for 2 hours and cooled naturally to obtain a product (ruthenium-nickel co-doped titanium oxide-based nanoparticle catalyst).

[0043] XRD was used to systematically study the morphology of the product prepared in this example. 2 correspond( Figure 4 ). LSV curve ( Figure 6 ) shows that at 10mA / cm 2 Under the condition of current density, it exhibits an overpotential of 81mV, which is on par with commercial Pt / C.

[0044] Example 6

[0045] In a 50 ml beaker, 20 mg of ruthenium chloride, 100 mg of nickel chloride, 1 g of titanium oxide, and 20 ml of deionized water were added in sequence and evaporated to dryness under magnetic stirring at 70°C to obtain solid intermediate product 1. 100 mg of solid intermediate product 1 was mixed with 20 mg of sodium hypophosphite monohydrate and ground in an agate mortar to obtain solid intermediate product 2. Solid intermediate product 2 was placed in a porcelain boat and heated under Ar / H 2The mixture was heated at 800° C. for 2 hours and cooled naturally to obtain a product (ruthenium and nickel co-doped titanium oxide-based nanoparticle catalyst).

[0046] XRD was used to systematically study the morphology of the product prepared in this example. 2 correspond( Figure 4 ). LSV curve ( Figure 6 ) shows that at 10mA / cm 2 It exhibits an overpotential of 130 mV under current density conditions, which is slightly lower than commercial Pt / C.

[0047] In summary, the ruthenium-nickel co-doped ruthenium nanoparticle catalyst synthesized in the present application not only has high catalytic activity in the hydrogen evolution reaction, but also has significantly improved stability compared to commercial Pt / C.

[0048] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0049] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for preparing a ruthenium-nickel co-doped titanium oxide-based nanoparticle catalyst, characterized in that: The following steps are involved: (1) Dissolution impregnation: using ruthenium chloride, nickel chloride, titanium oxide as precursors and deionized water as solvent, stirring at 50-80° C. for 6-8 hours until evaporated to dryness, to obtain a solid intermediate product 1; (2) Grinding: The solid intermediate product 1 is mixed with sodium hypophosphite monohydrate and then ground to obtain a solid intermediate product 2; (3) Annealing: The solid intermediate product 2 is heated at 500-800°C for 2-4 hours in an Ar / H2 mixed gas, and then cooled naturally to obtain the product.

2. The method for preparing the ruthenium-nickel co-doped titanium oxide-based nanoparticle catalyst according to claim 1, characterized in that: In step (1), the mass ratio of ruthenium chloride, nickel chloride and titanium oxide is (2-5): (10-20): (50-100).

3. The method for preparing the ruthenium-nickel co-doped titanium oxide-based nanoparticle catalyst according to claim 1, characterized in that: In step (2), the mass ratio of the solid intermediate product 1 to sodium hypophosphite monohydrate is 5:1 to 1:

1.

4. The method for preparing the ruthenium-nickel co-doped titanium oxide-based nanoparticle catalyst according to claim 1, characterized in that: In step (3), the concentration of H2 in the Ar / H2 mixed gas is between 2% and 5%.

5. A ruthenium-nickel co-doped titanium oxide-based nanoparticle catalyst prepared by the method according to any one of claims 1 to 4.

6. Use of the ruthenium-nickel co-doped titanium oxide-based nanoparticle catalyst according to claim 5 in hydrogen evolution reaction in alkaline water electrolysis.

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