CdS nano-particles with controllable lattice strain and preparation method and application thereof
By introducing controllable lattice strain into CdS nanoparticles and using C and N co-doping strategies, the problem of difficult-to-control catalyst lattice strain in the prior art is solved, and the efficiency and selectivity of CO2 reduction are improved.
Patent Information
- Application Number
- CN202510426553.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-07
- Publication Date
- 2025-07-08
AI Technical Summary
The prior art is difficult to achieve controllable lattice strain in metal sulfide catalysts by simple and efficient methods, resulting in limited CO generation efficiency in CO2 reduction reactions.
Coordinating polymer Cd3(C3N3S3)2(CdTMT) is used as the precursor, and the preparation of C and N co-doped CdS nanoparticles is controlled by adjusting the hydrothermal reaction temperature, thereby spontaneously forming a controllable tensile strain of 0 to 10% to optimize catalytic activity.
Controllable lattice strain of CdS nanoparticles is achieved, energy consumption is reduced, process is simplified, catalytic activity and selectivity of CO2 reduction is improved, and excellent electrocatalytic performance is shown.
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Figure CN120271032A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of electrocatalysts, and particularly relates to CdS nanoparticles with controllable lattice strain, a preparation method thereof, and uses thereof. Background Art
[0002] The electrochemical carbon dioxide reduction reaction (CO2RR) is crucial for realizing a closed carbon cycle and addressing climate challenges. Among them, efficient catalytic generation of carbon monoxide (CO) is the key to synthesizing high-value-added products. Metal sulfides (such as cadmium sulfide, CdS) have become potential catalysts for carbon dioxide (CO2) reduction due to their high conductivity and stability. However, their activation efficiency for CO2 molecules is limited by a relatively high reaction energy barrier (such as the *COOH intermediate formation step). Research has shown that by regulating the physical structure of the catalyst, the adsorption behavior of intermediates can be optimized. Therefore, constructing strain engineering by changing the lattice state provides a new idea for improving catalytic performance.
[0003] Strain engineering can significantly affect the d-orbital electron structure of transition metal sulfides by changing the atomic spacing and symmetry, thereby effectively regulating the electrochemical behavior of catalytic sites and improving catalytic performance. Currently, strain construction mainly relies on methods such as vacancy engineering, electrochemical reduction, or external stress loading. For example, Ag2S / Ag nanowires are electrochemically treated to remove S elements to construct microscopic strain on the defective Ag surface (ACS Nano 2023, 17, 2387 - 2398); by constructing sulfur vacancies in the CdS / Bi2S3-VS heterojunction structure, the surrounding atoms move towards the sulfur vacancies, thereby generating strong stress (J. Colloid Interface Sci. 2023, 224 - 234); compressive strain is induced in the MoS2 structure through the doping mechanism of N substituting S (Nano Lett 2016, 16, 5437 - 5443). However, these stress construction strategies for sulfides are usually limited to local small-scale lattice distortion and are difficult to effectively regulate their key active centers. In addition, the currently developed methods for introducing structural strain are often complex in process and highly dependent on the regulation of external components or heterostructures, which further increases the difficulty and uncontrollability of stress construction of metal sulfides. Therefore, it is crucial to design a reasonable strategy to construct large-area strain and create an in-situ stress environment by utilizing the intrinsic composition and structural characteristics of the material. Summary of the Invention
[0004] The technical problem to be solved by the present invention is to provide a method for preparing CdS nanoparticles with controllable lattice strain, using a coordination polymer Cd3(C3N3S3)2 (CdTMT, TMT=2,4,6-trimercaptotriazine anion) as a precursor, achieving controllable decomposition of TMT ligands by adjusting the hydrothermal reaction temperature, and inducing C and N co-doped CdS during the hydrothermal reaction to spontaneously form a controllable tensile strain of 0 to 10% in its lattice, thereby exhibiting excellent catalytic activity in the electrocatalytic CO2 reduction reaction to produce CO.
[0005] The technical problem to be solved by the present invention is achieved by adopting the following technical solutions:
[0006] One of the purposes of the present invention is to provide a method for preparing CdS nanoparticles with controllable lattice strain, comprising the following steps:
[0007] (1) A cadmium source and a sulfur source undergo coordination polymerization reaction to obtain a precursor;
[0008] (2) The precursor undergoes a hydrothermal reaction to obtain CdS nanoparticles.
[0009] The second object of the present invention is to provide a CdS nanoparticle with controllable lattice strain prepared by the above-mentioned preparation method.
[0010] The third object of the present invention is to provide the aforementioned CdS nanoparticles with controllable lattice strain as a catalyst for electrocatalytic CO2 reduction to produce CO.
[0011] The beneficial effects of the present invention are:
[0012] 1. The CdS nanoparticle preparation method provided by the present invention successfully achieves the controllable introduction of lattice stress inside CdS by controlling the hydrothermal reaction temperature. At the same time, the raw materials are easily available and the process is simple and efficient, avoiding the conventional high-temperature carbonization process, significantly reducing energy consumption, and is suitable for large-scale preparation.
[0013] 2. The present invention utilizes the inherent C and N elemental components of the precursor and spontaneously induces the formation of lattice microstrain during the CdS synthesis process through an in-situ doping strategy. This intrinsic strain induction mechanism not only avoids the traditional method's dependence on external components, but also establishes a clear relationship between strain and catalytic activity.
[0014] 3. The C atoms embedded in the CdS nanoparticle structure of the present invention not only cause it to form local tensile strain, but also act as an electron buffer to enhance the electron localization degree of the Cd site, thereby optimizing the CO2RR catalytic activity and having good CO production performance. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1Scanning electron microscope (SEM) image of CdTMT prepared in Example 1;
[0016] Figure 2 SEM image of CdTMT-170 prepared in Example 1;
[0017] Figure 3 SEM image of CdTMT-190 prepared in Example 2;
[0018] Figure 4 SEM image of CdTMT-150 prepared in Comparative Example 1;
[0019] Figure 5 X-ray diffraction (XRD) patterns of CdTMT prepared in Example 1, CdTMT-170, CdTMT-19 prepared in Example 2, and CdTMT-150 prepared in Comparative Example 1;
[0020] Figure 6 X-ray energy spectrum (EDX) pattern of CdTMT-170 prepared in Example 1;
[0021] Figure 7 High-angle annular dark-field scanning transmission electron microscope (HAADF-STEM) images of CdTMT-170 prepared in Example 1 and CdTMT-190 prepared in Example 2;
[0022] Figure 8 Williamson-Hall relationship diagrams of CdTMT-170 prepared in Example 1 and CdTMT-190 prepared in Example 2;
[0023] Figure 9 R-space curve and fitting curve of Cd K-edge FT-EXAFS in CdTMT-170 prepared in Example 1; wherein, the inset is a schematic model diagram of C, N-doped CdS;
[0024] Figure 10 Linear sweep voltammetry (LSV) curves of electrocatalytic CO2 reduction to CO using CdTMT and CdTMT-170 prepared in Example 1, CdTMT-19 prepared in Example 2, and CdTMT-150 prepared in Comparative Example 1 as catalysts respectively;
[0025] Figure 11 Faraday efficiency (FE CO ) diagrams of electrocatalytic CO2 reduction to CO using CdTMT and CdTMT-170 prepared in Example 1, CdTMT-19 prepared in Example 2, and CdTMT-150 prepared in Comparative Example 1 as catalysts respectively. Detailed implementation manners
[0026] In order to make the technical means, creative features, achieved purposes and effects of the present invention easy to understand, the present invention will be further described below in conjunction with specific embodiments and illustrations.
[0027] The present invention provides a method for preparing CdS nanoparticles with controllable lattice strain, comprising the following steps:
[0028] (1) A coordination polymerization reaction occurs between a cadmium source and a sulfur source to obtain a precursor;
[0029] (2) The precursor undergoes a hydrothermal reaction to obtain CdS nanoparticles.
[0030] Further, the cadmium source includes but is not limited to one or several of cadmium nitrate, cadmium chloride, cadmium sulfate and their hydrates.
[0031] Further, the sulfur source includes but is not limited to one or several of trisodium trithiocyanurate and trithiocyanuric acid. Trisodium trithiocyanurate and trithiocyanuric acid, on the one hand, act as sulfur sources to prepare a precursor through a coordination polymerization reaction with the cadmium source, and then CdS nanoparticles are prepared from the precursor through a hydrothermal reaction; on the other hand, they act as carbon sources and nitrogen sources to prepare carbon and nitrogen doped CdS nanoparticles and induce lattice strain.
[0032] Further, the molar ratio of the cadmium source to the sulfur source is (1.5 - 2):(1 - 1.5). Controlling the molar ratio of raw materials can not only prepare a precursor with a target structure, but also avoid waste of raw materials to the greatest extent and reduce costs.
[0033] Further, the coordination polymerization reaction between the cadmium source and the sulfur source is carried out in the form of an aqueous solution. In view of the characteristics that the cadmium source and the sulfur source are easily soluble in water, water is used as the reaction solvent to reduce the solvent cost and improve environmental protection.
[0034] Further, the reaction temperature of the coordination polymerization reaction is 20 - 30 °C. The coordination polymerization reaction can be carried out at room temperature to reduce the energy consumption cost. The reaction time of the coordination polymerization mainly depends on the reactant concentration and the reaction temperature.
[0035] Further, the reaction temperature of the hydrothermal reaction is 170 - 200 °C. The reaction temperature of the hydrothermal reaction affects the product structure and determines whether the product has lattice strain. The reaction time is controlled according to the reaction temperature, reactant concentration and precursor decomposition to reduce the energy consumption cost, shorten the preparation cycle and obtain the target product.
[0036] Further, the CdS nanoparticles are carbon and nitrogen doped CdS nanoparticles or pure CdS nanoparticles. Whether the CdS nanoparticles contain C and N atoms mainly depends on the reaction temperature of the hydrothermal reaction.
[0037] The present invention provides CdS nanoparticles with controllable lattice strain prepared by the foregoing preparation method.
[0038] The present invention also provides the use of the foregoing CdS nanoparticles with controllable lattice strain as a catalyst in the electrocatalytic reduction of CO2 to CO.
[0039] Example 1
[0040] Dissolve 1.85 g of cadmium nitrate tetrahydrate in 100 mL of deionized water to obtain Solution 1. Dissolve 0.97 g of trisodium salt of trithiocyanuric acid in 100 mL of deionized water to obtain Solution 2. Add Solution 2 dropwise to Solution 1 at a dropping rate of 200 mL / h. After the dropping is completed, stir and react at 25 °C for 24 h. After the reaction is completed, centrifuge and filter, wash the solid product with deionized water, and then freeze-dry at -60 °C for 8 h to obtain the precursor (CdTMT).
[0041] Add 10 mg of the precursor to 30 mL of deionized water, treat it under ultrasound at a frequency of 40 kHz for 20 min, transfer the obtained solution to a hydrothermal reaction kettle, and then place the hydrothermal reaction kettle in an oven at 170 °C for reaction for 5 h. After the reaction is completed, cool to room temperature, centrifuge and filter, wash the solid product with deionized water, and freeze-dry at -60 °C for 8 h to obtain CdS nanoparticles (CdTMT-170).
[0042] Example 2
[0043] According to the method of Example 1, the difference from Example 1 is that the hydrothermal reaction temperature is set to 190 °C to obtain CdS nanoparticles (CdTMT-190).
[0044] Example 3
[0045] According to the method of Example 1, the difference from Example 1 is that the hydrothermal reaction temperature is set to 200 °C to obtain CdS nanoparticles (CdTMT-200).
[0046] Example 4
[0047] According to the method of Example 1, the difference from Example 1 is that the amounts of cadmium nitrate tetrahydrate and trisodium salt of trithiocyanuric acid are adjusted, and the precursor is prepared by reacting 2.47 g of cadmium nitrate tetrahydrate and 1.46 g of trisodium salt of trithiocyanuric acid.
[0048] Example 5
[0049] According to the method of Example 1, the difference from Example 1 is that cadmium chloride monohydrate is used as the cadmium source.
[0050] Example 6
[0051] According to the method of Example 1, the difference from Example 1 is that: trithiocyanuric acid is used as the sulfur source.
[0052] Comparative Example 1
[0053] According to the method of Example 1, the difference from Example 1 is that: the hydrothermal reaction temperature is set at 150 °C to obtain the CdTMT / CdS composite material (CdTMT-150).
[0054] Figure 1 SEM image of CdTMT prepared in Example 1; Figure 2 SEM image of CdTMT-170 prepared in Example 1; Figure 3 SEM image of CdTMT-190 prepared in Example 2; Figure 4 SEM image of CdTMT-150 prepared in Comparative Example 1. It can be seen from Figures 1 to 4 that CdTMT-150 retains the original octahedral structure of CdTMT, but the surface of the catalyst gradually becomes rough and the porosity increases. As the hydrothermal reaction temperature increases, the octahedral structure of the precursor CdTMT is completely destroyed, forming smaller CdS nanoparticles.
[0055] Figure 5 XRD patterns of CdTMT prepared in Example 1, CdTMT-170, CdTMT-190 prepared in Example 2, and CdTMT-150 prepared in Comparative Example 1. It can be seen from Figure 5 that the diffraction peaks of CdTMT are sharp and strong, indicating good crystallinity; the characteristic peaks of CdTMT in CdTMT-150 weaken, while the characteristic peaks of CdS gradually appear, confirming the coexistence of these two components in the sample. As the hydrothermal reaction temperature increases, CdTMT decomposes to form CdS nanoparticles (CdTMT-170 and CdTMT-190). It is worth noting that compared with CdTMT-190 and CdS (PDF#77-2306), the diffraction peaks of CdTMT-170 shift significantly to smaller angles, indicating obvious tensile stress in the CdTMT-170 unit cell.
[0056] Figure 6 EDX image of CdTMT-170 prepared in Example 1. It can be seen from Figure 6 that S, C, N, and Cd in CdTMT-170 are evenly distributed, indicating that the original C and N atoms in the precursor are evenly dispersed in CdS, realizing the spontaneous induction of the formation of lattice microstrain during the material synthesis process through the in-situ doping strategy.
[0057] Figure 7 HAADF-STEM images of CdTMT-170 prepared in Example 1 and CdTMT-190 prepared in Example 2. It can be seen fromFigure 7 It is calculated that the lattice tensile strains of CdTMT-170 (d = 0.3570 nm) and CdTMT-190 (d = 0.3432 nm) are approximately 6.3% and 2.2% of that of CdS (PDF#77-2306, d = 0.3356 nm), respectively.
[0058] Figure 8 The Williamson-Hall relationship diagram of CdTMT-170 prepared in Example 1 and CdTMT-190 prepared in Example 2. Figure 8 It can be seen that with the increase of hydrothermal reaction temperature, the strain value of CdTMT-170 decreases from 0.414% to 0.169% of CdTMT-190.
[0059] Figure 9 The R space curve and fitting curve of the K-edge FT-EXAFS of Cd in CdTMT-170 prepared in Example 1; the inset is a schematic diagram of the model of C and N doped CdS. Figure 9 It can be seen that the curve is There is an obvious peak at , which corresponds to the scattering path of Cd-C / N / S, indicating that there may be other atomic coordination environments outside the Cd-S bond. Through fitting, it can be seen that the coordination numbers of Cd-S, Cd-C and Cd-N are 3, 4 and 1, respectively, and the average bond lengths are and Based on the coordination and bond length results, it can be concluded that the N atoms doped in CdTMT-170 directly replace the original S atoms, while the Cd-C bonds exist in CdS in the form of interstitial doping due to their longer average bond length (inset). In CdTMT-170, a large amount of C interstitial doping and a small amount of N substitutional doping induce tensile stress in CdS.
[0060] In summary, the hydrothermal reaction temperature has a significant effect on the product structure. When the hydrothermal reaction temperature is lower than 170°C, the obtained product is a CdTMT / CdS composite material. With the increase of the hydrothermal reaction temperature (170-190°C), the material components undergo a significant transformation: on the one hand, the CdS component in the composite material is gradually purified and the crystal structure tends to be perfect; on the other hand, the carbon and nitrogen doping content is reduced and the lattice stress is reduced. It is worth noting that CdTMT-170 retains moderate carbon and nitrogen doping, inducing a reasonable lattice stress distribution, which may be the key to its excellent electrocatalytic performance. When the hydrothermal reaction temperature is increased to 190°C, it will lead to a decrease in the content of doping elements and a decrease in stress, which in turn reduces the catalytic activity of the material. When the hydrothermal reaction temperature reaches 200°C, a pure CdS material without doping and stress is generated.
[0061] Using the products prepared in Example 1, Example 2, and Comparative Example 1 as catalysts respectively, 6 mg of the catalyst was weighed, and 250 μL of deionized water, 700 μL of isopropanol, and 50 μL of nafion solution were aspirated with a pipette and added to the catalyst, and ultrasonic treatment was carried out for 2 h at a frequency of 40 kHz. Subsequently, 30 μL of the slurry was aspirated with a pipette and evenly dropped on a carbon paper (specification: 14 mm × 5 mm, model: 711), and dried to obtain a working electrode. A platinum electrode was used as the counter electrode, and a silver / silver ion electrode was used as the reference electrode to assemble a three-electrode system. A CHI706E electrochemical workstation was used to monitor and plot linear sweep voltammetry curves (set potential: 0 to -2.7 V vs. Ag / Ag+, scan rate: 10 mv / s) and current-time curves (set potential: -1.9 to -2.7 V vs. Ag / Ag+, scan time: 1000 s). The electrolyte was composed of 1-butyl-3-methylimidazolium tetrafluoroborate and acetonitrile with a mass ratio of 3:7. Before measurement, CO2 was introduced (for about 15 min) to ensure that the electrolyte was a CO2-saturated solution, and at the same time, the residual air in the electrolytic cell was discharged to avoid affecting the experimental results. Finally, a gas chromatograph system (GC) was used for gas phase analysis of the products of electrocatalytic CO2 reduction.
[0062] Figure 10 LSV curves for electrocatalytic CO2 reduction to CO using CdTMT and CdTMT-170 prepared in Example 1, CdTMT-19 prepared in Example 2, and CdTMT-150 prepared in Comparative Example 1 as catalysts respectively. From Figure 10 it can be seen that the current density of CdTMT-170 in the CO2-saturated electrolyte is significantly higher than that of CdTMT, CdTMT-190, and CdTMT-150, indicating that CdTMT-170 is more suitable for electrocatalytic CO2 reduction to CO.
[0063] Figure 11 FE CO graphs for electrocatalytic CO2 reduction to CO using CdTMT and CdTMT-170 prepared in Example 1, CdTMT-19 prepared in Example 2, and CdTMT-150 prepared in Comparative Example 1 as catalysts respectively. From Figure 11 it can be seen that FE CO reaches the maximum value at -2.3 V. The FE CO of CdTMT-170 reaches 99.8% at -2.3 V. Compared with CdTM, CdTMT-190, and CdTMT-150, CdTMT-170 has stronger selectivity and electrocatalytic activity. In the low potential range (-1.9 to -2.1 V), although the FE COThe values are all higher than those of CdTMT-170, but the catalytic current is significantly lower than that of CdTMT-170.
[0064] The above electrochemical performance test results show that CdTMT-170 exhibits excellent electrocatalytic reduction performance for CO2. In the LSV test, CdTMT-170 shows a significantly higher current density in a CO2-saturated electrolyte than CdTMT, CdTMT-190, and CdTMT-150, indicating higher catalytic activity. At a potential of -2.3 V, the Faraday efficiency of CdTMT-170 for CO products is as high as 99.8%, showing almost perfect selectivity. These results fully demonstrate that CdTMT-170 combines high catalytic activity and excellent selectivity and is a highly promising and efficient electrocatalyst for CO2 reduction.
[0065] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.
Claims
1. A preparation method of CdS nanoparticles with controllable lattice strain, characterized in that, Comprising the following steps: (1) A coordination polymerization reaction occurs between a cadmium source and a sulfur source to obtain a precursor; (2) The precursor undergoes a hydrothermal reaction to obtain CdS nanoparticles.
2. The preparation method according to claim 1, characterized in that: The cadmium source is one or more of cadmium nitrate, cadmium chloride, cadmium sulfate, and their hydrates.
3. The preparation method according to claim 1, characterized in that: The sulfur source is one or more of trisodium trithiocyanurate and trithiocyanuric acid.
4. The preparation method according to claim 1, characterized in that: The molar ratio of the cadmium source to the sulfur source is (1.5 - 2):(1 - 1.5).
5. The preparation method according to claim 1, characterized in that: The cadmium source and the sulfur source carry out the coordination polymerization reaction in the form of an aqueous solution.
6. The preparation method according to claim 5, characterized in that: The reaction temperature of the coordination polymerization reaction is 20 - 30 °C.
7. The preparation method according to claim 1, characterized in that: The reaction temperature of the hydrothermal reaction is 170 - 200 °C.
8. The preparation method according to claim 1, characterized in that: The CdS nanoparticles are carbon and nitrogen doped CdS nanoparticles or pure CdS nanoparticles.
9. CdS nanoparticles with controllable lattice strain prepared by the preparation method according to any one of claims 1 - 8.
10. Use of the CdS nanoparticles with controllable lattice strain according to claim 9 as a catalyst in the electrocatalytic reduction of CO2 to CO.