An amorphous Pd-MoS2 thin film, its preparation method and application

Abstract

This invention provides an amorphous Pd-MoS2 thin film, its preparation method, and its application, belonging to the field of hydrogen evolution catalyst development technology. This invention prepares an amorphous Pd-MoS2 thin film by magnetron sputtering, where Pd flakes are tightly bonded to a MoS2 target. Pd doping replaces adjacent Mo sites, altering the band structure of MoS2 and introducing conductive electronic states around the Fermi level. This enhances the metallic properties of MoS2, improving conductivity and catalytic activity, thus solving the problem of insufficient performance in existing hydrogen evolution catalysts. The amorphous Pd-MoS2 thin film provided by this invention exhibits good conductivity and excellent hydrogen evolution catalytic performance when used as a hydrogen evolution catalyst.

Description

Technical Field

[0001] This invention relates to the field of hydrogen evolution catalyst development technology, and in particular to an amorphous Pd-MoS2 thin film, its preparation method, and its application. Background Technology

[0002] Hydrogen is a very clean and efficient energy carrier with a very high calorific value per unit mass, and its only byproduct after combustion is water, which can be produced on a large scale through water electrolysis. However, in actual reactions, the reaction intermediates formed on the electrode surface need to overcome a relatively high energy barrier, thus requiring a suitable catalyst to reduce the overpotential required for water electrolysis.

[0003] Molybdenum disulfide (MoS2) is abundant, possesses good catalytic performance, and is more inexpensive. It is a layered compound similar to graphite, with numerous exposed Mo-S facets in single-atom-layer MoS2, providing a large number of electrocatalytic hydrogen production active sites. It shows great promise as a cheaper catalyst with superior hydrogen evolution catalysis, potentially replacing the precious metal platinum. However, pure MoS2 has poor electrical conductivity, and its catalytic active sites are located at the edges; excessive crystallinity can actually hinder the full realization of its catalytic performance.

[0004] Chinese patent CN114507875A discloses a molybdenum disulfide catalyst with tunable phase composition and large interlayer spacing, its preparation method, and its application. Combining phase engineering and the strain effect introduced by intercalated ions, the molybdenum disulfide catalyst prepared using an ethanol-preferential reduction strategy exhibits a high 1T phase content (73.5%) and additional ammonium ion intercalation. The ammonium ion insertion results in a larger interlayer spacing (0.95 nm), more active sites, and a faster charge transfer rate for the molybdenum disulfide catalyst. Furthermore, the local tensile strain on the basal surface caused by the ammonium ion insertion further optimizes the hydrogen adsorption of sulfur atoms on the catalyst surface.

[0005] However, the existing molybdenum disulfide catalyst products have complex preparation methods, which are not conducive to actual production, and their catalytic performance needs to be improved. Summary of the Invention

[0006] The purpose of this invention is to provide an amorphous Pd-MoS2 thin film, its preparation method, and its application. The preparation method is simple, and the resulting amorphous Pd-MoS2 thin film has good conductivity and can effectively improve the catalytic hydrogen evolution efficiency.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0008] This invention provides a method for preparing amorphous Pd-MoS2 thin films, comprising the following steps:

[0009] By attaching Pd thin sheets tightly to a MoS2 target, a composite target is obtained;

[0010] Amorphous Pd-MoS2 thin films were obtained by depositing a film on a substrate material using the composite target.

[0011] The coating method is magnetron sputtering.

[0012] Preferably, in the composite target material, the atomic ratio of Pd to MoS2 is 1:8 to 120.

[0013] Preferably, the Pd sheet is subjected to one or more ultrasonic treatments before being tightly attached to the MoS2 target.

[0014] Preferably, the substrate material is one or more of ITO glass and FTO glass.

[0015] Preferably, the substrate material undergoes one or more ultrasonic treatments before coating.

[0016] Preferably, the liquid medium used in the ultrasonic treatment is one or more of water, ethanol, acetone or hydrochloric acid;

[0017] The ultrasonic frequency of the ultrasonic treatment is 5-20Hz, and the power density is 50-150W.

[0018] The ultrasonic treatment time is 0.1 to 1 hour.

[0019] Preferably, the substrate material is partially covered before coating, and the covered area accounts for 5-50% of the total surface area.

[0020] The covering material is one or more of the following: double-sided tape, high-temperature tape, or correction fluid.

[0021] Preferably, the vacuum level used in the magnetron sputtering is 1×10⁻⁶. -2 ~1×10 -5 Pa;

[0022] The magnetron sputtering uses a sputtering gas pressure of 0.5–5 Pa;

[0023] The preferred power for magnetron sputtering is 30–200W.

[0024] The present invention also provides an amorphous Pd-MoS2 thin film obtained by the above preparation method.

[0025] The present invention also provides the application of the above-mentioned amorphous Pd-MoS2 thin film as a hydrogen evolution catalyst.

[0026] The beneficial effects of this invention are:

[0027] This invention prepares amorphous Pd-MoS2 thin films by magnetron sputtering of Pd sheets tightly bonded to a MoS2 target. Pd doping replaces adjacent Mo sites, altering the band structure of MoS2 and introducing conductive electronic states around the Fermi level, thus enhancing the metallic properties of MoS2 and improving its conductivity and catalytic activity. Furthermore, the amorphous nanocrystalline catalyst exhibits high dispersion, and Pd doping increases the induction efficiency of the 2H-to-1T phase transition, resulting in more active Pd-S-Mo sites and further increasing the active site density. Therefore, the amorphous Pd-MoS2 thin film provided by this invention exhibits good conductivity and excellent hydrogen evolution catalytic performance when used as a hydrogen evolution catalyst. Attached Figure Description

[0028] Figure 1 XRD pattern of hydrogen evolution catalyst in amorphous Pd-MoS2 thin film;

[0029] Figure 2 TEM image of the hydrogen evolution catalyst in amorphous Pd-MoS2 thin film;

[0030] Figure 3 LSV diagram of the hydrogen evolution catalyst for amorphous Pd-MoS2 thin film;

[0031] Figure 4 Photograph of Pd sheet after the target material is attached;

[0032] Figure 5 This is a schematic diagram showing the placement of the Pd sheet. Detailed Implementation

[0033] This invention provides a method for preparing amorphous Pd-MoS2 thin films, comprising the following steps:

[0034] By attaching Pd thin sheets tightly to a MoS2 target, a composite target is obtained;

[0035] Amorphous Pd-MoS2 thin films were obtained by depositing a film on a substrate material using the composite target.

[0036] The coating method is magnetron sputtering.

[0037] In this invention, the atomic ratio of Pd to MoS2 in the composite target is preferably 1:8 to 120. Preferably, the atomic ratio of Pd to MoS2 in the composite target is controlled by the amount of Pd sheet used.

[0038] In this invention, the Pd sheet is preferably subjected to one or more ultrasonic treatments before being tightly bonded to the MoS2 target. The liquid medium used for the ultrasonic treatment is preferably one or more of water, ethanol, acetone, or hydrochloric acid. The ultrasonic frequency of the ultrasonic treatment is preferably 5-20 Hz, and the power density is preferably 50-150 W. The ultrasonic treatment time is preferably 0.1-1 h. When the ultrasonic treatment is performed multiple times, the liquid medium and parameters used for each ultrasonic treatment may be different. The purpose of the ultrasonic treatment is to remove surface impurities and surface oxide layers to avoid the impurities and oxide layers affecting the performance of the subsequent amorphous Pd-MoS2 film. In this invention, the Pd sheet is preferably bonded to the MoS2 target by adhesive bonding, preferably using conductive adhesive, double-sided adhesive, or other similar materials.

[0039] In this invention, the substrate material is preferably one or more of ITO glass and FTO glass; before coating, one surface of the substrate material is preferably partially covered, with the covered area preferably accounting for 5-50% of the total surface area; the covering material is preferably one or more of double-sided tape, high-temperature tape, or correction fluid; the substrate material is preferably subjected to one or more ultrasonic treatments before coating. The liquid medium used for ultrasonic treatment is preferably one or more of water, ethanol, acetone, or hydrochloric acid; the ultrasonic frequency of ultrasonic treatment is preferably 5-20Hz, and the power density is preferably 50-150W; the ultrasonic treatment time is preferably 0.1-1h. When ultrasonic treatment is performed multiple times, the liquid medium and parameters used for each ultrasonic treatment can be different; the purpose of ultrasonic treatment is to remove surface impurities of the substrate material to avoid affecting subsequent coating.

[0040] In this invention, the vacuum level used in the magnetron sputtering is preferably 1×10⁻⁶. -2 ~1×10 -5 Pa, more preferably 1×10 -3 ~1×10 -4 Pa; the sputtering gas pressure used in the magnetron sputtering is 0.5-5 Pa, and the sputtering gas pressure is preferably controlled by introducing plasma gas, preferably Ar gas; the power used in the magnetron sputtering is preferably 30-200 W; during the magnetron sputtering process, the film thickness is controlled by controlling the sputtering time to obtain an amorphous Pd-MoS2 thin film, and the sputtering time can be selected from 3 to 90 min.

[0041] The present invention also provides an amorphous Pd-MoS2 thin film obtained by the above preparation method, wherein the thickness of the amorphous Pd-MoS2 thin film is preferably 10 to 800 nm.

[0042] The present invention also provides the application of the above-mentioned amorphous Pd-MoS2 thin film as a hydrogen evolution catalyst.

[0043] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0044] Example 1

[0045] Add 30 ml of ethanol to a 100 ml beaker, and place a 5 × 20 mm container inside. 2 Five ITO glass slides were prepared, and the beaker was then placed in an ultrasonic apparatus for ultrasonic treatment at a frequency of 15 Hz, a power density of 100 W, and a duration of 0.5 h. After treatment, the glass was quickly dried with a hair dryer. A 5×5 mm [unclear text - possibly a type of adhesive] was then attached to one end of the conductive surface. 2 The high-temperature tape was fixed on the sample stage and then placed into the vacuum chamber of the magnetron sputtering instrument.

[0046] Add 30ml of acetone to a 100ml beaker, place a Pd sheet inside, and sonicate for 0.5 hours at a frequency of 15Hz and a power density of 100W. After sonication, place the beaker in a 100ml beaker, add 30ml of ethanol, and sonicate for 5 minutes. Then add 30ml of hydrochloric acid to a 100ml beaker, place the Pd sheet inside, and sonicate for 0.5 hours at a frequency of 15Hz and a power density of 100W. After sonication, place the beaker in a 100ml beaker, add 30ml of ethanol, and sonicate for 5 minutes at a frequency of 15Hz and a power density of 100W. After sonication, quickly dry the beaker with a hairdryer. Cut the beaker into four 5×5mm pieces. 2 Thin sheets are symmetrically attached to a sputtering track ring of a 60mm diameter MoS2 target using conductive silver paste, and the target is then loaded into a magnetron sputtering instrument.

[0047] The vacuum level in the vacuum chamber of the magnetron sputtering instrument is evacuated to 4 × 10⁻⁶. -4 At Pa, Ar gas was introduced, the sputtering gas pressure was adjusted to 0.8 Pa, the sputtering power was set to 90 W, and sputtering was carried out for 45 min to obtain an amorphous Pd-MoS2 thin film.

[0048] Example 2

[0049] Add 30 ml of ethanol to a 100 ml beaker, and place a 5×20 mm beaker inside. 2 Five ITO glass sheets and one silicon wafer were used. The beaker was then placed in an ultrasonic apparatus for ultrasonic treatment at a frequency of 15 Hz, a power density of 100 W, and a duration of 0.5 h. After treatment, it was quickly dried with a hair dryer. A 5×5 mm [unclear text - possibly a type of adhesive] was attached to one end of the conductive surface. 2 The high-temperature tape was fixed on the sample stage and then placed into the vacuum chamber of the magnetron sputtering instrument.

[0050] Add 30ml of acetone to a 100ml beaker, place a Pd sheet inside, and sonicate for 0.5 hours at a frequency of 15Hz and a power density of 100W. After sonication, place the beaker in a 100ml beaker, add 30ml of ethanol, and sonicate for 5 minutes. Then add 30ml of hydrochloric acid to a 100ml beaker, place the Pd sheet inside, and sonicate for 0.5 hours at a frequency of 15Hz and a power density of 100W. After sonication, place the beaker in a 100ml beaker, add 30ml of ethanol, and sonicate for 5 minutes at a frequency of 15Hz and a power density of 100W. After sonication, quickly dry the beaker with a hairdryer. Cut the beaker into six 5×5mm pieces. 2 Thin sheets are symmetrically attached to a ring of sputtering tracks on a MoS2 target using conductive silver paste, and the target is then loaded into a magnetron sputtering instrument.

[0051] The vacuum level in the vacuum chamber of the magnetron sputtering instrument is evacuated to 4 × 10⁻⁶. -2 At Pa, Ar gas was introduced, the sputtering gas pressure was adjusted to 0.5 Pa, the sputtering power was set to 90 W, and sputtering was carried out for 25 min to obtain an amorphous Pd-MoS2 thin film.

[0052] Example 3

[0053] Add 30 ml of ethanol to a 100 ml beaker, and place a 5×20 mm beaker inside. 2 Five ITO glass sheets and one silicon wafer were used. The beaker was then placed in an ultrasonic apparatus for ultrasonic treatment at a frequency of 15 Hz, a power density of 100 W, and a duration of 0.5 h. After treatment, it was quickly dried with a hair dryer. A 5×5 mm [unclear text - possibly a type of adhesive] was attached to one end of the conductive surface. 2 The high-temperature tape was fixed on the sample stage and then placed into the vacuum chamber of the magnetron sputtering instrument.

[0054] Add 30ml of acetone to a 100ml beaker, place a Pd sheet inside, and sonicate for 0.5 hours at a frequency of 15Hz and a power density of 100W. After sonication, place the beaker in a 100ml beaker, add 30ml of ethanol, and sonicate for 5 minutes. Then add 30ml of hydrochloric acid to a 100ml beaker, place the Pd sheet inside, and sonicate for 0.5 hours at a frequency of 15Hz and a power density of 100W. After sonication, place the beaker in a 100ml beaker, add 30ml of ethanol, and sonicate for 5 minutes at a frequency of 15Hz and a power density of 100W. After sonication, quickly dry the beaker with a hairdryer. Cut the beaker into eight 5×5mm pieces. 2 Thin sheets are symmetrically attached to a ring of sputtering tracks on a MoS2 target using conductive silver paste, and the target is then loaded into a magnetron sputtering instrument.

[0055] The vacuum level in the vacuum chamber of the magnetron sputtering instrument is evacuated to 4 × 10⁻⁶. -5At Pa, Ar gas was introduced, the sputtering gas pressure was adjusted to 5.0 Pa, the sputtering power was set to 90 W, and sputtering was carried out for 65 min to obtain an amorphous Pd-MoS2 thin film.

[0056] Experimental Example

[0057] The preparation method is the same as in Example 1, except that the number of Pd films is set to 4, 6 and 8 respectively, and the performance of the obtained amorphous Pd-MoS2 films is tested.

[0058] First, X-ray diffraction (XRD) was used to analyze the crystal structure of the sample within the range of 10°–70° and a scan rate of 5° / min. Then, scanning electron microscopy (SEM) was used to analyze the morphology and micro-area composition of the sample. Finally, linear sweep voltammetry (LSV) was performed using a three-electrode system in 0.5 mol / L H₂SO₄ electrolyte to characterize its electrochemical hydrogen evolution catalytic performance.

[0059] The obtained XRD pattern is as follows Figure 1 As shown;

[0060] XRD patterns of three groups of MoS2 thin films with different Pd doping contents are shown below. Figure 1 The diffraction peaks of the MoS2 film at 33° and 61.8° correspond to the (100) and (112) crystal planes of its hexagonal (2H-MoS2) crystal system, respectively. Other MoS2 diffraction peaks, such as those at 39.8°, 48.9° and 57°, showed varying degrees of small bulges and no obvious crystallization peaks.

[0061] This indicates that the (100) and (112) crystal planes of the thin film are parallel to the surface, while other crystal planes such as (002) are perpendicular to the surface, making most of the sample appear amorphous, with some small crystalline regions of specific orientations interspersed in the middle, thus making the entire sample present an amorphous nanocrystalline morphology.

[0062] TEM image Figure 2 As shown;

[0063] TEM images of the thin film show that it is dense and uniform, with high dispersion and no aggregation. Some fine grains are interspersed within, also uniformly dispersed. The density of Pd-MoS2 is better than that of pure MoS2, resulting in more catalytically active sites. Selected area electron diffraction (SAED) patterns also show no single-crystal diffraction spots; the diffraction rings of polycrystalline materials have relatively blurred edges, consistent with the characteristics of amorphous materials and XRD results. Elemental mapping analysis (EDX) of the thin film confirms the presence of Mo, S, and Pd elements, and these elements are observed to be highly uniformly dispersed, demonstrating that Pd is very uniformly doped into the MoS2 thin film.

[0064] Pd doping replaces adjacent Mo sites, altering the band structure of MoS2 and introducing conductive electronic states around the Fermi level. This enhances the metallic properties of MoS2, improving its conductivity and catalytic activity. Furthermore, the amorphous nanocrystalline catalyst exhibits high dispersion; Pd doping increases the induction efficiency of the 2H-to-1T phase transition, resulting in more active Pd-S-Mo sites and further increasing the active site density.

[0065] LSV diagram as follows Figure 3 As shown, the corresponding data results are shown in Table 1 below.

[0066] Table 1. Data Results Corresponding to LSV Charts

[0067]

[0068] Polarization curves of three groups of MoS2 films doped with different numbers of Pd layers were obtained using linear sweep voltammetry (LSV). The results showed that, compared to pure MoS2 films, the polarization curves at 10 mA / cm² were significantly different. 2 The overpotential under current density first decreases and then increases with the increase of Pd doping amount. Among them, when 4 Pd chips are attached, there is a lower overpotential of 226mV and a higher exchange current density.

[0069] Photo of a target with 4 Pd plates attached, as shown Figure 4 As shown in the diagram, the pasting location is as follows: Figure 5 As shown.

[0070] In summary, the Pd-MoS2 film with four Pd patches exhibits lower overpotential, better kinetic activity, and faster charge transfer efficiency, thus demonstrating superior catalytic hydrogen evolution performance. This can be attributed to the introduction of more active Pd-S-Mo catalytic sites by Pd doping, coupled with the better dispersibility of films prepared by magnetron sputtering, which allows Pd atoms to be uniformly dispersed within the MoS2 film. This results in a more uniform distribution of active sites and enhances the synergistic effect between Pd atoms and the MoS2 nanostructure, improving carrier mobility, increasing material conductivity, and ultimately enhancing the catalytic hydrogen evolution efficiency of the Pd-MoS2 film. However, as the amount of Pd atoms increases, excessive disruption of the original MoS2 structure occurs, while the number of newly introduced catalytic active sites is insufficient to offset or even surpass the original catalytic structure. Therefore, more Pd atom doping is not necessarily better; the Pd-MoS2 film with four Pd patches achieves optimal catalytic hydrogen evolution performance, at which point the atomic proportion of Pd atoms in the film is 3.58%.

[0071] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an amorphous Pd-MoS2 thin film, characterized in that, Includes the following steps: By attaching Pd thin sheets tightly to a MoS2 target, a composite target is obtained; Amorphous Pd-MoS2 thin films were obtained by depositing a film on a substrate material using the composite target. The coating method is magnetron sputtering; In the composite target, the atomic ratio of Pd to MoS2 is 1:8~120; The substrate material is one or more of ITO glass and FTO glass; Before coating, a portion of the substrate material is masked, with the masked area accounting for 5-50% of the total surface area. The covering material is one or more of the following: double-sided tape, high-temperature tape, or correction fluid.

2. The preparation method according to claim 1, characterized in that, The Pd sheet is subjected to one or more ultrasonic treatments before being closely attached to the MoS2 target.

3. The preparation method according to claim 1, characterized in that, The substrate material undergoes one or more ultrasonic treatments before coating.

4. The preparation method according to claim 2 or 3, characterized in that, The liquid medium used in the ultrasonic treatment is one or more of water, ethanol, acetone or hydrochloric acid. The ultrasonic frequency of the ultrasonic treatment is 5~20Hz, and the power density is 50~150W; The ultrasonic treatment time is 0.1~1h.

5. The preparation method according to claim 1, characterized in that, The magnetron sputtering uses a vacuum level of 1×10⁻⁶. -2 ~1×10 -5 Pa; The magnetron sputtering uses a sputtering gas pressure of 0.5~5 Pa; The preferred power for magnetron sputtering is 30~200W.

6. An amorphous Pd-MoS2 thin film obtained by the preparation method according to any one of claims 1 to 5.

7. The application of the amorphous Pd-MoS2 thin film according to claim 6 as a hydrogen evolution catalyst.

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