An oxygen vacancy zirconium oxide-supported nano-ruthenium catalyst and its preparation method and application

Abstract

The present invention relates to the field of electrocatalyst technology, specifically a vacancy zirconium oxide-loaded nano-ruthenium catalyst, a preparation method, and an application thereof. Zirconium nitrate is used as a raw material, and after being fully mixed with a ruthenium chloride solution and hydrothermally processed, a powder precursor is obtained, which is then subjected to pyrolysis treatment to form a ruthenium oxide-loaded ruthenium powder rich in oxygen vacancies, which is a hydrogen evolution reaction electrocatalyst. The present invention first dissolves zirconium nitrate and ruthenium chloride in ethanol, combines them at the atomic level through a hydrothermal reaction, and then forms a crystalline and amorphous zirconium oxide interface, as well as an interface between zirconium oxide and ruthenium after carbonization under a low-temperature protective gas. The raw materials are mainly zirconium nitrate and ruthenium chloride, which are low in cost, can be prepared in large quantities, are easy to commercialize, can be used as an excellent HER catalyst, have high catalytic activity and good stability, and can be widely used in water electrolysis devices.

Description

Technical Field

[0001] The present invention relates to the technical field of electrocatalysts, and in particular to an oxygen vacancy zirconium oxide-supported nano-ruthenium catalyst, a preparation method and an application thereof. Background Art

[0002] Currently, alkaline water electrolysis is the most mature and commercialized technology, but it faces the challenge of slow HER rates, resulting in low efficiency. Proton adsorption capacity is crucial for HER activity. However, alkaline electrolytes require a prior water dissociation process to generate sufficient protons for the reaction. This necessity significantly slows the kinetics of alkaline HER. Therefore, in addition to optimizing proton adsorption strength, it is also important to simultaneously reduce the energy barrier for water dissociation when designing HER electrocatalysts for alkaline media. Ruthenium, with its similar proton binding energy to Pt and lower price, has been widely studied as a Pt alternative in HER. Constructing hydrogen spillover-based binary (HSBB) systems by dispersing active materials on supports with water dissociation capabilities, such as metal oxides and hydroxides, has proven to be an effective strategy for enhancing alkaline HER activity. However, in such systems, hydrogen spillover from the metal oxide / hydroxide support to the metal center is a thermodynamically unfavorable process. Furthermore, the built-in electric field established between the metal and its support leads to charge accumulation at the interface, which imparts strong proton-trapping capabilities and increases the barrier to hydrogen spillover. Therefore, accelerating hydrogen spillover in HSBB systems is a major challenge.

[0003] The work function difference (ΔΦ) between a metal and its support significantly influences interfacial proton adsorption, thereby influencing hydrogen spillover. Based on this theory, it is reasonable to tune the work function of the scaffold to promote energetically and kinetically favorable hydrogen spillover processes. Oxides with cations whose d-bands are considered completely empty, such as ZrO2, TiO2, HfO2, and WO3, are well-suited as supports with tunable work functions due to their propensity to form oxygen vacancies (Vo). This phenomenon leads to the emergence of filled and occupied interstitial states in the d-band, resulting in shifts in the Fermi level and work function. Vo can induce charge transfer from the support to the metal and promote hydrogen spillover. Furthermore, the amorphous nature of the support significantly affects catalytic activity. The disordered and loosely bonded amorphous phase creates abundant dangling bonds and unsaturated coordination configurations, which promote dd electron transfer and intermediate to long-range p-π orbital coupling, thereby facilitating charge transfer between active sites and enhancing HER activity. Therefore, amorphous / crystalline zirconia-supported nano-ruthenium with rich oxygen vacancies is urgently needed as an efficient electrocatalyst for alkaline HER. Summary of the Invention

[0004] In view of the above situation, in order to overcome the defects of the prior art, the present invention provides an oxygen vacancy zirconia-loaded nano-ruthenium catalyst and its preparation method and application to solve the problems involved in the background technology.

[0005] To achieve the above objectives, the present invention provides the following technical solution: an oxygen vacancy zirconium oxide-loaded nano-ruthenium catalyst, which uses zirconium nitrate as raw material, is fully mixed with a ruthenium chloride solution and hydrothermally prepared to obtain a powder precursor, which is then pyrolyzed to form an oxygen vacancy-rich zirconium oxide-loaded nano-ruthenium hydrogen evolution reaction electrocatalyst.

[0006] Preparation method of oxygen vacancy zirconium oxide supported nano-ruthenium catalyst,

[0007] 1) Add ruthenium chloride (RuCl3·xH2O) and zirconium nitrate (Zr(NO3)4·5H2O) to ethanol and stir at room temperature to obtain an ethanol solution containing ruthenium and zirconium;

[0008] 2) pouring the formed ethanol solution containing ruthenium and zirconium into a polytetrafluoroethylene liner for hydrothermal reaction to obtain a precursor powder containing ruthenium and zirconium;

[0009] 3) The precursor powder is calcined in a tube furnace at 200-400°C using a carbonization process to obtain ruthenium-doped zirconia powder.

[0010] Furthermore, the mass ratio of ruthenium chloride to zirconium nitrate in (1) is 1:3, the concentration of ruthenium chloride in the ethanol solution is 0.27 mg / ml, and the concentration of zirconium nitrate in the ethanol solution is 0.8 mg / ml.

[0011] Furthermore, the hydrothermal temperature in (2) is 200° C., and the hydrothermal time is 4 h.

[0012] Furthermore, the calcination in (3) is carried out for 1 h, and the calcination atmosphere is argon.

[0013] Application of oxygen vacancy zirconia loaded nano-ruthenium catalysts. Oxygen vacancy zirconia loaded nano-ruthenium catalysts are used as electrocatalysts in hydrogen evolution reaction.

[0014] Furthermore, the application steps include:

[0015] (1) Disperse the catalyst and XC-72 powder in a mixed solution of nafion and ethanol;

[0016] (2) Dropping the catalyst solution onto the glassy carbon electrode to obtain a working electrode;

[0017] (3) The graphite rod and standard hydrogen electrode were used as the working electrode and reference electrode, respectively, and tested in 1 M KOH electrolyte.

[0018] Furthermore, the mass ratio of the catalyst to XC-72 is 3:1.

[0019] Furthermore, the mass concentration of the nafion is 5 wt.%.

[0020] Furthermore, the volume ratio of the nafion and ethanol is 1:10, and the mass volume ratio of the catalyst and nafion is 1:10.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention first dissolves zirconium nitrate and ruthenium chloride in ethanol, combines them at the atomic level through a hydrothermal reaction, and then undergoes carbonization under a cryogenic protective atmosphere to form interfaces between crystalline and amorphous zirconium oxide, as well as between zirconium oxide and ruthenium oxide. The raw materials, primarily zirconium nitrate and ruthenium chloride, are low-cost, can be produced in large quantities, and are easily commercialized. This catalyst can be used as an excellent HER catalyst with high catalytic activity and good stability, making it widely applicable in water electrolysis devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a SEM image of the oxygen vacancy zirconia-supported nano-ruthenium catalyst according to an embodiment of the present invention;

[0024] Figure 2 This is a TEM image of the oxygen vacancy zirconia-supported nano-ruthenium catalyst according to an embodiment of the present invention;

[0025] Figure 3 This is a linear sweep voltammetry curve of the HER of the oxygen vacancy zirconia-supported nano-ruthenium catalyst in alkaline electrolyte according to an embodiment of the present invention;

[0026] Figure 4 This is a Tafel slope diagram of the oxygen vacancy zirconia-supported nano-ruthenium catalyst in alkaline electrolyte according to an embodiment of the present invention;

[0027] Figure 5 This is a graph showing the electrochemical activity area of ​​the oxygen vacancy zirconia-supported nano-ruthenium catalyst in alkaline electrolyte according to an embodiment of the present invention;

[0028] Figure 6 This is a graph showing the long-term stability of the oxygen vacancy zirconia-supported nano-ruthenium catalyst in alkaline electrolyte according to an embodiment of the present invention; DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Example 1:

[0030] An oxygen vacancy zirconium oxide supported nano-ruthenium catalyst is prepared from zirconium nitrate as raw material. After being fully mixed with a ruthenium chloride solution and hydrothermally processed, a powder precursor is obtained. The precursor is then pyrolyzed to form an oxygen vacancy-rich zirconium oxide supported nano-ruthenium electrocatalyst for hydrogen evolution reaction.

[0031] Preparation method of oxygen vacancy zirconium oxide supported nano-ruthenium catalyst,

[0032] 1) Add 20 mg of ruthenium chloride (RuCl3·xH2O) and 60 mg of zirconium nitrate (Zr(NO3)4·5H2O) to 75 mL of ethanol and stir at room temperature to obtain an ethanol solution containing ruthenium and zirconium.

[0033] 2) Pour the ethanol solution containing ruthenium and zirconium into the polytetrafluoroethylene liner and heat it at 5 ℃ min -1 The temperature is raised to 200-400°C at a rate of 10000 ℃ and maintained for 1 hour in an argon atmosphere to obtain a precursor powder containing ruthenium and zirconium;

[0034] 3) The precursor powder is calcined in a tube furnace at 200-400°C using a carbonization process to obtain ruthenium-doped zirconia powder.

[0035] Figure 1 This is the SEM image of the oxygen vacancy zirconia-supported nano-ruthenium catalyst;

[0036] Figure 2 TEM image of oxygen vacancy zirconia supported nano-ruthenium catalyst; Example 2:

[0037] Application of oxygen vacancy zirconia-supported nano-ruthenium catalyst: oxygen vacancy zirconia-supported nano-ruthenium catalyst is used as an electrocatalyst in hydrogen evolution reaction. The application steps include:

[0038] 3 mg of catalyst and 1 mg of XC-72 powder were dispersed in a mixture of 30 μL of 5 wt.% Nafion and 300 μL of ethanol. After 30 minutes of sonication, a homogeneous catalyst ink was obtained. 9 μL of the catalyst ink was then dropped onto a glassy carbon electrode and allowed to dry at room temperature to form a working electrode.

[0039] Performance testing:

[0040] The HER catalytic activity of the above products in 1 M KOH electrolyte was tested using a graphite rod and a standard hydrogen electrode (RHE) as the counter electrode and reference electrode, respectively. Figure 3 As shown in the figure, the current density of electrode sample No. 1 (heat treatment temperature = 300 °C, red line) in 1 M KOH electrolyte reaches 10 mA cm -2 When the overpotential is 14 mV, the overpotential of electrode sample No. 2 (heat treatment temperature = 200℃) and electrode sample No. 3 (heat treatment temperature = 400℃) reaches 51 mV and 31 mV respectively; while the overpotential of commercial Pt / C is only 19 mV.

[0041] Depend on Figure 4 It can be seen that the Tafel slope of sample No. 1 is only 26.9 mV dec -1 , while those of sample No. 2, sample No. 3 and commercial Pt / C were 40.6 mV dec −1 、36.1 mV dec −1 and 35.4 mV dec −1 , it can be concluded that sample No. 1 has good reaction kinetics.

[0042] Figure 5 The electrochemically active areas of samples 1, 2, and 3 were compared. Sample 1 had an electrochemically active area of ​​28.4 mF cm −2 , sample No. 2 is 7.9 mF cm -2 , sample No. 3 is 8.9 mF cm -2 , from which it can be concluded that sample No. 1 has more active sites.

[0043] like Figure 6 As shown, the current density is 10 mA cm in 1 M KOH electrolyte. -2 A 20-hour stability test was conducted, and the voltage hardly changed. The catalytic activity and stability were significantly better than those of commercial Pt / C.

[0044] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. An oxygen vacancy zirconium oxide supported nano-ruthenium catalyst, characterized in that: Zirconium nitrate and ruthenium chloride are first dissolved in ethanol and solvent-heated to obtain a powder precursor, which is then pyrolyzed to form a zirconia-loaded nano-ruthenium electrocatalyst rich in oxygen vacancies for hydrogen evolution reaction. The catalyst preparation method comprises: 1) Add ruthenium chloride (RuCl3·xH2O) and zirconium nitrate (Zr(NO3)4·5H2O) to ethanol and stir at room temperature to obtain an ethanol solution containing ruthenium and zirconium; 2) Pour the formed ethanol solution containing ruthenium and zirconium into a polytetrafluoroethylene liner for a solvothermal reaction to obtain a precursor powder containing ruthenium and zirconium; the solvothermal temperature is 200°C and the solvothermal time is 4 hours; 3) calcining the precursor powder in a tube furnace at 200°C under an argon atmosphere by a carbonization process to obtain an oxygen vacancy zirconia-supported nano-ruthenium catalyst; The mass ratio of ruthenium chloride to zirconium nitrate in step (1) is 1:3, In step (3), the calcination is carried out for 1 h.

2. The method for preparing the oxygen vacancy zirconia-supported nano-ruthenium catalyst according to claim 1, characterized in that: 1) Ruthenium chloride (RuCl3·xH2O) and zirconium nitrate (Zr(NO3)4·5H2O) were added to ethanol and stirred at room temperature to obtain an ethanol solution containing ruthenium and zirconium. The solvothermal temperature was 200°C and the solvothermal time was 4 hours. 2) pouring the formed ethanol solution containing ruthenium and zirconium into a polytetrafluoroethylene liner for solvothermal reaction to obtain a precursor powder containing ruthenium and zirconium; 3) calcining the precursor powder in a tube furnace at 200°C under an argon atmosphere by a carbonization process to obtain an oxygen vacancy zirconia-supported nano-ruthenium catalyst; The mass ratio of ruthenium chloride to zirconium nitrate in step (1) is 1:3, In step (3), the mixture was calcined for 1 h.

3. The method for preparing an oxygen vacancy zirconium oxide-supported nano-ruthenium catalyst according to claim 2, characterized in that: In step (1), the concentration of ruthenium chloride in the ethanol solution is 0.27 mg / ml, and the concentration of zirconium nitrate in the ethanol solution is 0.8 mg / ml.

4. Use of the oxygen vacancy zirconium oxide-supported nano-ruthenium catalyst according to claim 1 or the catalyst prepared by the method according to any one of claims 2 to 3, characterized in that: The oxygen vacancy zirconium oxide loaded nano-ruthenium catalyst is used as an electrocatalyst in hydrogen evolution reaction.

5. The use of the oxygen vacancy zirconium oxide supported nano-ruthenium catalyst according to claim 4, characterized in that: The application steps include: (1) Dispersing the catalyst and XC-72 powder in a mixed solution of nafion and ethanol; (2) Dropping the catalyst solution onto the glassy carbon electrode to obtain a working electrode; (3) The graphite rod and standard hydrogen electrode were used as the working electrode and reference electrode, respectively, and tested in 1 M KOH electrolyte.

6. The use of an oxygen vacancy zirconium oxide-supported nano-ruthenium catalyst according to claim 5, characterized in that: The mass ratio of the catalyst to XC-72 is 3:

1.

7. The use of an oxygen vacancy zirconium oxide supported nano-ruthenium catalyst according to claim 6, characterized in that: The mass concentration of the nafion is 5 wt.%.

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