A method to improve the performance of molybdenum ditelluride catalytic methanol reforming for hydrogen production through surface oxidation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- BEIJING INST OF TECH
- Filing Date
- 2025-12-17
- Publication Date
- 2026-05-26
Smart Images
Figure CN122076472A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method for improving the performance of molybdenum ditelluride catalytic methanol reforming for hydrogen production through surface oxidation, belonging to the field of catalytic chemistry. Background Technology
[0002] Molybdenum ditelluride (MoTe2) is a typical two-dimensional transition metal chalcogenide (TMDC) compound, which mainly consists of two phases: a semiconductor phase (2H phase) and a half-metal phase (1T' phase). The 2H phase of MoTe2 has a layered structure and tunable electronic properties. The 2H phase has fewer bulk active sites, with edge sites being the main focus. However, through defect engineering, heterogeneous boundary construction, and single-atom doping / loading, the activity and selectivity can be significantly improved without sacrificing stability. Therefore, it is regarded as a non-noble metal catalytic material platform with both cost and performance potential.
[0003] Oxygen plasma is a highly reactive ionized gas formed by the partial ionization of oxygen (O2) under discharge conditions, containing O, O2, and O2. - O 2- O 3- Particles such as ozone (O3) and ultraviolet photons possess both physical bombardment and chemical reactivity; they can achieve organic matter removal / ashing, hydrophilic activation (introducing oxygen-containing functional groups such as -OH and -COOH), and surface roughening on material surfaces, and are commonly used in processes such as plasma cleaning and surface modification.
[0004] Methanol, due to its high hydrogen content (12.5 wt%), safe storage and transportation, and low toxicity, is considered an ideal liquid hydrogen storage medium. Photocatalytic methanol reforming can achieve hydrogen release under mild conditions, while avoiding the high energy consumption and CO2 emissions problems required by traditional thermocatalysis. Currently, the three main types of catalysts commonly used in methanol reforming for hydrogen production are: 1. Noble metal supported catalysts, which have advantages such as high activity, good selectivity, and recyclability. Their stability and resistance to poisoning can be further enhanced by selecting suitable supports and promoters. Their main disadvantages are high cost, sensitivity to poisons such as sulfur / lead leading to easy deactivation, and the possibility of sintering at high temperatures leading to a decrease in activity. 2. Non-noble metal catalysts, which have low cost, abundant resources, and good thermal stability in perovskite, spinel, and other systems. However, their overall activity and selectivity are generally lower than those of noble metals, and their lifespan is relatively short. 3. Single-atom catalysts, which have high atom utilization (close to 100%) and uniform and well-defined active sites, thus exhibiting ultra-high intrinsic activity and excellent selectivity, and are easy to separate and reuse. However, its preparation process is complex and costly, and its long-term stability in practical applications still faces challenges, especially the tendency to agglomerate or deactivate under complex reaction conditions. Summary of the Invention
[0005] To address the issue of existing hydrogen production methods failing to balance cost and performance, this invention aims to provide a method for enhancing the hydrogen production performance of molybdenum ditelluride-catalyzed methanol reforming through surface oxidation. This method involves in-situ modification of the 2H-phase molybdenum ditelluride surface using oxygen plasma to enhance methanol reforming hydrogen production. A non-uniform oxide-doped layer is constructed on the 2H-phase molybdenum ditelluride surface using oxygen plasma, introducing abundant oxygen species to generate oxygen-doped molybdenum ditelluride. This invention not only alters the valence state of Mo, adjusting the electron cloud density and shifting the Fermi level downwards, but also forms micro-pn junctions on the surface, thereby significantly accelerating the kinetics of the methanol reforming reaction, achieving superior adsorption and activation sites, and improving hydrogen production activity.
[0006] The objective of this invention is achieved through the following technical solution:
[0007] The method for improving the performance of molybdenum ditelluride catalytic methanol reforming for hydrogen production by surface oxidation disclosed in this invention includes the following steps:
[0008] Step 1: Place the 2H phase molybdenum ditelluride grown by chemical vapor deposition in an oxygen plasma cleaner for oxidation treatment to obtain an oxide doped layer on the surface. The oxygen-doped molybdenum ditelluride is used to improve the catalytic performance of molybdenum ditelluride in methanol reforming to produce hydrogen.
[0009] Step 2: Add methanol aqueous solution and oxygen-doped molybdenum ditelluride to a quartz reactor; irradiate with light to produce hydrogen and formaldehyde.
[0010] The illumination time is 3-12 hours, and the temperature inside the quartz reactor is 25℃.
[0011] The principle of this method is as follows: surface modification of 2H phase molybdenum ditelluride is performed to form oxygen-doped molybdenum ditelluride, which generates micro PN junctions. Methanol cleaning exposes the local PN junctions as catalytic active sites for methanol recombination to produce hydrogen, thereby accelerating the methanol recombination to produce hydrogen.
[0012] The 2H phase molybdenum distelluride thin film was grown on a silicon / silicon oxide substrate with a thickness of 10 nm by chemical vapor deposition.
[0013] The oxidation treatment parameters were 40W for 30s.
[0014] Beneficial effects:
[0015] 1. The present invention discloses a method for improving the performance of molybdenum ditelluride catalytic methanol reforming for hydrogen production through surface oxidation, using molybdenum (3 ppm) as the catalyst.
[0016] The catalyst uses tellurium (1.9 yuan / g) and platinum (1.9 yuan / g) as raw materials, rather than precious metal catalysts (such as platinum, 300+ yuan / g), so the preparation cost of this catalyst is significantly lower than that of conventional precious metal catalysts.
[0017] 2. The method disclosed in this invention for improving the catalytic performance of molybdenum ditelluride in methanol reforming through surface oxidation achieves an optimal catalytic performance of 149.3 mmol g for oxygen-doped molybdenum ditelluride. -1 h -1 It is comparable to conventional precious metal catalysts.
[0018] 3. The method disclosed in this invention for improving the performance of molybdenum ditelluride catalytic methanol reforming to produce hydrogen through surface oxidation uses oxygen plasma treatment for surface oxidation. This method is simple to operate and takes very little time (only 30 seconds of oxidation treatment is required), so it can quickly and conveniently obtain a high-performance oxygen-doped molybdenum ditelluride catalyst for catalytic methanol reforming to produce hydrogen.
[0019] 4. The method for improving the performance of molybdenum ditelluride catalytic methanol reforming to produce hydrogen disclosed in this invention via surface oxidation produces naturally separated gaseous hydrogen and high-value-added liquid formaldehyde, thus eliminating the presence of carbon-containing greenhouse gases (CO). x ) component emissions.
[0020] 5. The method disclosed in this invention for improving the performance of molybdenum ditelluride catalytic methanol reforming for hydrogen production through surface oxidation, while efficiently generating two important industrial products, hydrogen and formaldehyde, is convenient for low-carbon and environmentally friendly production.
[0021] 6. This invention discloses a method for improving the performance of molybdenum ditelluride (MoD) catalyzed methanol reforming for hydrogen production through surface oxidation. The method involves in-situ modification of the 2H-phase MoD surface using oxygen plasma to enhance hydrogen production during methanol reforming. A non-uniform oxide-doped layer is constructed on the 2H-phase MoD surface using oxygen plasma, introducing abundant oxygen species to generate oxygen-doped MoD. This invention not only alters the valence state of Mo, adjusting the electron cloud density and lowering the Fermi level, but also forms micro-pn junctions on the surface, significantly accelerating the kinetics of the methanol reforming reaction. Compared to intrinsic Te defects, the Mo-O bonding interface provides superior adsorption and activation sites for the CH3O* intermediate, with the O atom acting as a negative charge center to effectively lower the reaction energy barrier and improve overall catalytic efficiency. The catalyst performance initially increases and then decreases with increasing oxidation time. The material exhibits the highest hydrogen production activity at an oxidation time of 30 s, reaching 149.3 mmol g in the liquid-phase methanol reforming hydrogen production reaction. -1 h-1 exhibits 5.5 times better performance than the untreated raw material. Attached Figure Description
[0022] Figure 1 The scanning transmission electron microscopy characterization of oxygen-doped molybdenum ditelluride is shown in Figure a, which shows the large-size morphology, Figure b, which shows the fine local morphology, and Figures c and d, which show the distribution of Te and O elements in the region of Figure a. This figure shows that the doping region of oxygen-doped molybdenum ditelluride is the surface layer of the sample.
[0023] Figure 2 The X-ray photoelectron spectroscopy characterization of molybdenum ditelluride before and after oxygen doping is shown in Figures a and b. Figures c and d show the characterization results of Mo and O elements before oxidation, and the figures show the characterization results of Mo and O elements after oxidation. The figures show that the content of Mo-O bonds increases after oxidation.
[0024] Figure 3 The Kelvin probe force microscopy characterization of molybdenum ditelluride after methanol cleaning is shown in Figure a. The unoxidized sample is shown in Figure b. The sample oxidized for 30 seconds is shown in Figure b. This figure shows that the oxidation treatment produces non-uniform P-type doping on the surface of molybdenum ditelluride, exposing highly active catalytic sites, which will generate micro PN junctions and thus accelerate the methanol reorganization to hydrogen production.
[0025] Figure 4 The graph shows the evolution of Gibbs free energy during the catalytic process as calculated theoretically. Compared with the intrinsic Te vacancy active sites of the sample, the Mo-O active sites generated by oxygen doping have a lower reaction energy barrier, which verifies that the improvement in catalytic performance comes from oxygen doping.
[0026] Figure 5 To investigate the evolution of the catalytic performance of methanol reforming for hydrogen production under the same oxygen plasma treatment power (40 W) at different oxidation treatment times, the performance first increased and then decreased with increasing treatment time, reaching its optimal value (149.3 mmol g) after 30 s treatment. -1 h-1) improves the performance of raw materials by 5.5 times compared to untreated raw materials.
[0027] Figure 6 The chart compares the performance of oxygen-doped molybdenum ditelluride (MoD2) catalyst with that of noble metal-doped catalyst (Pt-TiO2). The performance of the oxygen-doped MoD2 catalyst reaches 149.3 mmol g. -1 h-1, far exceeding the catalytic performance of Pt-TiO2 (19.70 mmol g). -1 h-1).
[0028] Figure 7 This is a schematic diagram of the treatment of oxygen-doped molybdenum ditelluride catalyst. The 2H phase molybdenum ditelluride is surface-oxidized by oxygen plasma treatment to obtain oxygen-doped molybdenum ditelluride, and then the highly active catalytic sites are exposed by methanol cleaning. Detailed Implementation
[0029] To better illustrate the purpose and advantages of the present invention, the invention will be further described below in conjunction with the accompanying drawings and examples.
[0030] Example 1:
[0031] The method for improving the performance of molybdenum ditelluride catalytic methanol reforming for hydrogen production disclosed in this embodiment is implemented through the following steps:
[0032] Step 1: Select chemical vapor deposition (CVD) to grow a 10 nm thick 2H phase molybdenum distearate film on a silicon / silicon oxide substrate, such as... Figure 1 As shown in (b), the lattice of the molybdenum ditelluride thin film is a 2H phase;
[0033] Step 2: Surface oxidation of the 2H-phase molybdenum ditelluride grown on a silicon / silicon oxide substrate was performed using oxygen plasma for 40 W 30 s to obtain oxygen-doped molybdenum ditelluride. The oxygen-doped molybdenum ditelluride was characterized by scanning transmission electron microscopy, and the results are as follows: Figure 1 As shown in (d), oxygen plasma treatment produces an oxide-doped layer on the surface, and X-ray photoelectron spectroscopy characterization also shows a significant enhancement of the oxidation signal on the surface after oxygen plasma oxidation treatment. Figure 2 As shown;
[0034] Step 3: The unstable oxide layer adhering to the surface is removed by washing with methanol, thereby exposing highly active catalytic sites. Characterization by Kelvin probe force microscopy shows that non-uniform P-type doping exists on the surface, such as... Figure 3 As shown, a micro PN junction will be generated, thereby accelerating the methanol reorganization process to produce hydrogen;
[0035] Step 4: Following the methanol-to-hydrogen performance testing method, the catalytic performance of oxygen-doped molybdenum ditelluride was tested. The performance was as follows: Figure 5 As shown in (a), the oxygen-doped molybdenum ditelluride treated with 40W 30S oxygen plasma achieved a performance of 149.3 mmol g. -1 h-1 exhibits a 5.5-fold performance improvement over untreated raw materials, exceeding that of common precious metal catalysts.
[0036] This invention significantly improves the catalytic performance of 2H-phase molybdenum ditelluride prepared by chemical vapor deposition by using oxygen plasma to modify its surface.
[0037] ① Oxidation treatment of 2H phase molybdenum ditelluride was carried out by oxygen plasma for 40w 30s to generate local PN junctions. The local PN junctions were exposed by methanol cleaning and used as catalytic active sites for methanol recombination to produce hydrogen.
[0038] ②The 2H phase molybdenum distelluride thin film should be a 10 nm thick 2H phase molybdenum distelluride thin film grown on a silicon / silicon oxide substrate by chemical vapor deposition.
[0039] ③ The optimal oxygen plasma treatment parameters should be 40W 30s.
[0040] Comparative Example 1
[0041] The performance of oxygen-doped molybdenum ditelluride with different oxygen plasma oxidation times was compared, such as... Figure 5 As shown, the catalytic performance first increases and then decreases with increasing treatment time. However, the catalytic performance of the samples treated with oxygen plasma oxidation is better than that of the unoxidized samples. The catalytic performance of the samples treated with 40w 30s parameters reaches the maximum value, which is 5.5 times higher than that of the untreated samples.
[0042] Comparative Example 2
[0043] Compared with the performance of noble metal catalysts (Pt-TiO2) in published papers, the oxygen-doped molybdenum ditelluride catalyst obtained by this method achieves a performance of 149.3 mmol g. -1 h-1, far exceeding the catalytic performance of Pt-TiO2 (19.70 mmol g). -1 h-1), such as Figure 6 As shown.
[0044] The test method for methanol-to-hydrogen performance is as follows:
[0045] (1) Prepare a photocatalyst, the photocatalyst is... Figure 5 Oxygen-doped molybdenum ditelluride thin films prepared in [the process];
[0046] (2) Add 1 ml of methanol aqueous solution and thin film photocatalyst to 4 ml of quartz reactor;
[0047] (3) Irradiate the quartz reactor in step (2) with a 300W xenon lamp or monochromatic light source that simulates sunlight for 3-12 hours. The temperature inside the quartz reactor is 25°C, which produces hydrogen and formaldehyde.
[0048] (4) The specific hydrogen content produced in step (3) was determined by gas chromatography. The test results of the gas chromatography are as follows: Figure 4 As shown. The hydrogen production rate was 149.3 mmol g. -1 h -1 It is comparable to conventional precious metal platinum catalysts.
[0049] The above detailed description further illustrates the purpose, technical solution, and beneficial effects of the invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for improving the performance of molybdenum ditelluride catalytic methanol reforming for hydrogen production through surface oxidation, characterized in that: Includes the following steps: Step 1: Place the 2H phase molybdenum ditelluride grown by chemical vapor deposition in an oxygen plasma cleaner for oxidation treatment to obtain an oxide doped layer on the surface. The oxygen-doped molybdenum ditelluride is used to improve the catalytic performance of molybdenum ditelluride in methanol reforming to produce hydrogen. Step 2: Add the methanol aqueous solution and oxygen-doped molybdenum ditelluride to the quartz reactor; When exposed to light, hydrogen and formaldehyde are produced.
2. The method for improving the performance of molybdenum ditelluride catalytic methanol reforming for hydrogen production by surface oxidation as described in claim 1, characterized in that: The illumination time is 3-12 hours, and the temperature inside the quartz reactor is 25℃.
3. The method for improving the performance of molybdenum ditelluride catalytic methanol reforming for hydrogen production by surface oxidation as described in claim 1 or 2, characterized in that: Surface modification of 2H phase molybdenum ditelluride forms oxygen-doped molybdenum ditelluride, which generates micro PN junctions. Methanol cleaning exposes these local PN junctions, which serve as catalytic active sites for methanol reorganization to produce hydrogen, thus accelerating the methanol reorganization to produce hydrogen.
4. The method for improving the performance of molybdenum ditelluride catalytic methanol reforming for hydrogen production by surface oxidation as described in claim 3, characterized in that: The 2H phase molybdenum distelluride thin film was grown on a silicon / silicon oxide substrate with a thickness of 10 nm by chemical vapor deposition.
5. The method for improving the performance of molybdenum ditelluride catalytic methanol reforming for hydrogen production by surface oxidation as described in claim 4, characterized in that: The oxidation treatment parameters were 40W for 30s.