A synthesis method of cadmium telluride grown in situ on tungsten trioxide surface
By growing cadmium telluride in situ on the surface of tungsten trioxide to form a tightly bonded heterojunction, the problems of low photogenerated charge separation efficiency of WO3 and easy corrosion of CdTe were solved, achieving high efficiency photocatalytic performance and improved material stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANTONG UNIV
- Filing Date
- 2026-02-27
- Publication Date
- 2026-06-09
AI Technical Summary
In existing technologies, tungsten trioxide (WO3) has low photogenerated charge separation efficiency, and cadmium telluride (CdTe) materials are easily corroded and have poor interfacial contact, which limits photocatalytic performance.
Using blue tungsten trioxide rich in oxygen vacancies as a self-reducing agent and growth template, cadmium telluride was grown in situ on its surface by ultraviolet light treatment, forming a tightly bonded WO3/CdTe heterojunction.
It significantly improves the photogenerated charge separation efficiency, enhances the stability and photocatalytic performance of the material, reduces the recombination rate of photogenerated electrons and holes, and improves photocurrent response and quantum efficiency.
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Figure CN122164444A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of catalyst material preparation technology, and in particular to a method for synthesizing cadmium telluride by in-situ growth on the surface of tungsten trioxide. Background Technology
[0002] Photocatalysis technology, due to its green and sustainable characteristics, is considered one of the potential ways to simultaneously solve the problems of environmental pollution and energy shortage.
[0003] Tungsten trioxide (WO3), a widely used semiconductor photocatalytic material, possesses a small band gap energy of approximately 2.6 eV, enabling it to generate a broad spectral response and absorb a wider range of visible light. WO3 exhibits excellent catalytic oxidation capabilities, along with superior photoelectric activity and chemical stability. However, its charge extraction efficiency is relatively low, and the photogenerated electrons and holes generated during the photocatalytic process are prone to recombination.
[0004] Cadmium telluride (CdTe), a narrow bandgap semiconductor material, has a bandgap energy of approximately 1.45 eV, which closely matches the terrestrial solar spectrum and is widely used in the photovoltaic field. However, CdTe still faces two major drawbacks: firstly, CdTe has poor resistance to photocorrosion; secondly, CdTe exhibits low photogenerated carrier separation efficiency during photocatalysis, limiting its photocatalytic performance. Summary of the Invention
[0005] This application provides a method for synthesizing cadmium telluride (CdTe) by in-situ growth on the surface of tungsten trioxide (WO3). This method aims to solve the technical problems in the prior art, such as the low photo-generated charge separation efficiency of WO3, the susceptibility of CdTe materials to photocorrosion, and the poor contact at the simple composite interface between the two. By using blue WO3 rich in oxygen vacancies as a self-reducing agent and growth template, the core technical solution of in-situ chemical bonding growth of CdTe is achieved. This results in the construction of tightly bonded heterojunctions, significantly improved photo-generated charge separation efficiency and material stability, thereby obtaining high-performance photocatalytic composite materials.
[0006] This application provides a method for synthesizing cadmium telluride by in-situ growth on the surface of tungsten trioxide, specifically including the following steps:
[0007] S1 Preparation of blue tungsten trioxide rich in oxygen vacancies: Specifically, tungsten trioxide is dispersed in formaldehyde solution, subjected to ultraviolet light treatment, and then washed to obtain blue tungsten trioxide;
[0008] S2 The blue tungsten trioxide, tellurium dioxide and cadmium source obtained in step S1 are mixed in an alkaline aqueous solution. The blue tungsten trioxide is heated to react and cadmium telluride is grown in situ on the surface of the blue tungsten trioxide to form a WO3 / CdTe heterocomposite material.
[0009] Preferably, the tungsten trioxide in step S1 is tungsten trioxide nanorods.
[0010] Preferably, the cadmium source in step S2 is cadmium chloride.
[0011] Preferably, the ultraviolet irradiation time in step S1 is 2 to 5 minutes.
[0012] The present invention also provides a WO3 / CdTe heterocomposite material prepared according to any of the above methods.
[0013] One technical solution provided in this application embodiment has at least the following technical effects:
[0014] 1. This invention is the first to use blue tungsten trioxide (WO3) rich in oxygen vacancies as both a reaction carrier and an internal reducing agent to grow cadmium telluride (CdTe) in situ on its surface. This method avoids the need for external reducing agents and ensures that a heterojunction interface with atomically close and large-area contact is formed between CdTe and the WO3 substrate, laying the structural foundation for efficient interfacial charge transfer.
[0015] 2. The WO3 / CdTe heterostructure material prepared by this invention can effectively promote the spatial separation of photogenerated carriers and significantly reduce the electron-hole recombination rate, thereby significantly improving the photocurrent response and quantum efficiency of the material. At the same time, CdTe is effectively protected by WO3, and the stability of WO3 itself is also enhanced, which together slows down the photocorrosion of the material and improves the long-term operational stability of the composite material in the photocatalytic process. Attached Figure Description
[0016] Figure 1 The WO3 nanorods of Example 3 of this application ( Figure 1 a) In-situ growth of CdTe on the surface of WO3 nanorods Figure 1 b) Field emission scanning electron microscope image;
[0017] Figure 2 This is the energy spectrum of CdTe grown in situ on the surface of WO3 nanorods in Example 3 of this application;
[0018] Figure 3 This is a transient photocurrent test diagram of CdTe grown in situ on the surface of WO3 nanorods under different reflux times in Example 3 of this application. Detailed Implementation
[0019] This application provides a synthesis method that achieves in-situ semiconductor growth without the need for external reducing agents, utilizing the properties of the carrier itself. This offers a new strategy to address the problems of weak interfacial bonding and limited performance improvement in traditional heterojunction materials.
[0020] The technical solution in this application is to solve the above problems, and the overall approach is as follows:
[0021] First, by treating WO3 with ultraviolet light in a formaldehyde solution, abundant oxygen vacancies are created, transforming it into a highly reducing "blue WO3". This is not merely a color change, but a fundamental alteration of its surface chemical properties, providing active sites and driving forces for subsequent reactions. Next, the crucial reducing power of this "blue WO3" is utilized to reduce Cd in an alkaline aqueous solution. 2+ CdTe was synthesized by directly reducing TeO2 on its surface. This process enabled in-situ chemical bonding growth of CdTe on WO3, rather than physical attachment, thus ensuring a tight electronic coupling structure between the two. Ultimately, this meticulous inside-out construction optimized the resulting WO3 / CdTe composite material in terms of band structure, charge transport pathway, and interfacial stability, synergistically enhancing its photocatalytic performance.
[0022] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.
[0023] Example 1
[0024] 0.3478 g of commercially available tungsten trioxide powder was ultrasonically dispersed in a 37% formaldehyde solution, irradiated with a 400 W ultraviolet high-pressure mercury lamp for 15 min, centrifuged, and washed with water and ethanol to obtain blue tungsten trioxide (WO3) rich in oxygen vacancies.
[0025] Add 100 mL of 0.02 mol·L⁻¹ -1 Add 2 mmol of mercaptopropionic acid to an aqueous solution of cadmium chloride, and use 1 mol·L⁻¹ - 1 The pH of the NaOH solution was adjusted to 10.5 and is ready for use.
[0026] 0.0479 g of tellurium dioxide and blue tungsten trioxide were dispersed and mixed evenly in 10 mL of water. After the mixture turned gray, it was immediately added to the prepared cadmium chloride aqueous solution. The mixture was heated under reflux for 2.5 h. Samples were taken every 0.5 h. The samples were centrifuged, washed, and dried to form a heterojunction of cadmium telluride in situ on the surface of tungsten trioxide. The product was a WO3 / CdTe heterocomposite material, labeled as Sample-P-15min-CdCl2.
[0027] Example 2
[0028] 0.3478 g of commercially available tungsten trioxide powder was ultrasonically dispersed in a 37% formaldehyde solution, irradiated with a 400 W ultraviolet high-pressure mercury lamp for 15 min, centrifuged, and washed with water and ethanol to obtain blue tungsten trioxide rich in oxygen vacancies.
[0029] Add 100 mL of 0.02 mol·L⁻¹ -1 Add 2 mmol of mercaptopropionic acid to an aqueous solution of cadmium nitrate, and use 1 mol·L⁻¹ -1 The pH of the NaOH solution was adjusted to 10.5 and is ready for use.
[0030] 0.0479 g of tellurium dioxide and blue tungsten trioxide were dispersed and mixed evenly in 10 mL of water. After the mixture turned gray, it was immediately added to an aqueous solution of cadmium nitrate and heated under reflux for 2.5 h. Samples were taken every 0.5 h, and the samples were centrifuged, washed, and dried. Cadmium telluride was grown in situ on the surface of tungsten trioxide to form a heterojunction. The product was a WO3 / CdTe heterocomposite material, labeled as Sample-P-15min-Cd(NO3)2.
[0031] Example 3
[0032] 1.5 mmol of laboratory-prepared tungsten trioxide nanorods were ultrasonically dispersed in 37% formaldehyde solution, irradiated with a 400 W ultraviolet high-pressure mercury lamp for 2 min, centrifuged, and washed with water and ethanol to obtain blue tungsten trioxide nanorods rich in oxygen vacancies.
[0033] Add 100 mL of 0.02 mol·L⁻¹ -1 Add 2 mmol of mercaptopropionic acid to an aqueous solution of cadmium chloride, and use 1 mol·L⁻¹ -1 The pH of the NaOH solution was adjusted to 10.5 and is ready for use.
[0034] 0.0479 g of tellurium dioxide and blue tungsten trioxide nanorods were dispersed and uniformly mixed in 10 mL of water. After the mixture turned gray, it was immediately added to an aqueous solution of cadmium chloride and heated under reflux for 2.5 h. Samples were taken every 0.5 h, and the samples were centrifuged, washed, and dried. Cadmium telluride was grown in situ on the surface of the tungsten trioxide nanorods to form a heterojunction. The product was a WO3 / CdTe heterocomposite material, labeled as Sample-NR-2min-CdCl2.
[0035] Example 4
[0036] 1.5 mmol of laboratory-prepared tungsten trioxide nanorods were ultrasonically dispersed in 37% formaldehyde solution, irradiated with a 400 W ultraviolet high-pressure mercury lamp for 5 min, centrifuged, and washed with water and ethanol to obtain blue tungsten trioxide nanorods rich in oxygen vacancies.
[0037] Add 100 mL of 0.02 mol·L⁻¹ -1 Add 2 mmol of mercaptopropionic acid to an aqueous solution of cadmium nitrate, and use 1 mol·L⁻¹ -1 The pH of the NaOH solution was adjusted to 10.5 and is ready for use.
[0038] 0.0479 g of tellurium dioxide and blue tungsten trioxide nanorods were dispersed and uniformly mixed in 10 mL of water. After the mixture turned gray, it was immediately added to an aqueous solution of cadmium nitrate and heated under reflux for 2.5 h. Samples were taken every 0.5 h, and the samples were centrifuged, washed, and dried. Cadmium telluride was grown in situ on the surface of the tungsten trioxide nanorods to form a heterojunction. The product was a WO3 / CdTe heterocomposite material, labeled as Sample-NR-5min-Cd(NO3)2.
[0039] The four samples from Examples 1-4 were tested under the same conditions. The results showed that: in Example 1, the CdTe in Sample-P-15min-CdCl2 did not completely cover the WO3 powder surface, the distribution was uneven, and there was agglomeration; the photocurrent density was 1.74 μA·cm. -2 After 5 cycles, the photocurrent decayed by more than 40%. Cyclic photocurrent experiments suggest that CdTe may be detached.
[0040] In Example 2, the CdTe in Sample-P-15min-Cd(NO3)2 was also not completely covered on the WO3 powder surface, was unevenly distributed, and showed agglomeration; photocurrent density: 1.59 μA·cm -2 After 5 cycles, the photocurrent decayed by more than 40%.
[0041] In Example 3, Sample-NR-2min-CdCl2's CdTe is uniformly and densely coated on the surface of WO3 nanorods in an ultrathin layer, forming a perfect core-shell structure. The elemental signals of W, Cd, and Te highly overlap and are continuous in the nanorod region, strongly indicating the formation of an atomically tightly bound chemical interface. Please refer to... Figures 1-2 , Figure 1 Field emission scanning electron microscope (FESEM) images of WO3 nanorods (a) and CdTe grown in situ on the surface of WO3 nanorods (b). It can be clearly observed that the tungsten trioxide surface is completely covered by cadmium telluride. Figure 2 The energy spectrum of CdTe grown in situ on the surface of WO3 nanorods further confirms the in-situ growth of cadmium telluride on the tungsten trioxide surface. Photocurrent density: 3.51 μA·cm⁻¹ -2 After 5 cycles, the photocurrent retention rate is >90%. Please refer to [reference needed]. Figure 3 , Figure 3 The transient photocurrent test results show that the heterostructure can effectively promote the separation of photogenerated electrons and holes, improve material stability, and enhance photocatalytic performance.
[0042] The CdTe layer of Sample-NR-5min-Cd(NO3)2 in Example 4 is relatively thick, with some areas showing agglomeration, and its coating uniformity is inferior to that of Sample-NR-2min-CdCl2 in Example 3; photocurrent density: 3.18 μA·cm -2 After 5 cycles, the photocurrent retention rate was >80%.
[0043] In summary, the WO3 / CdTe heterocomposite material of Example 3 of this application exhibits the best overall performance. Specifically, the regular morphology of the WO3 nanorods provides an ideal epitaxial growth template for CdTe, and the appropriate amount of oxygen vacancies formed by short-term irradiation serve as uniform active sites, promoting the two-dimensional layered epitaxial growth of CdTe. The perfect core-shell structure and tight interface greatly promote interfacial charge transfer and inhibit bulk and surface recombination. The dense and uniform CdTe coating layer and strong interfacial chemical bonds effectively protect WO3 from electrolyte corrosion while inhibiting photocorrosion of CdTe due to hole accumulation. The excellent photoelectric properties of the WO3 / CdTe heterocomposite material directly translate into higher apparent quantum efficiency and catalytic activity.
[0044] This invention creatively utilizes the reducing properties of blue tungsten trioxide to grow narrow-bandgap semiconductor cadmium telluride in situ on its surface, providing a novel approach and method for the research, development, production, and commercial application of photocatalytic composite materials.
[0045] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the invention.
[0046] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.
Claims
1. A method for synthesizing cadmium telluride by in-situ growth on the surface of tungsten trioxide, characterized in that, Specifically, the following steps are included: S1 Preparation of blue tungsten trioxide rich in oxygen vacancies: Specifically, tungsten trioxide is dispersed in formaldehyde solution, subjected to ultraviolet light treatment, and then washed to obtain blue tungsten trioxide; S2 The blue tungsten trioxide, tellurium dioxide and cadmium source obtained in step S1 are mixed in an alkaline aqueous solution. The blue tungsten trioxide is heated to react and cadmium telluride is grown in situ on the surface of the blue tungsten trioxide to form a WO3 / CdTe heterocomposite material.
2. The method for synthesizing cadmium telluride by in-situ growth on the surface of tungsten trioxide as described in claim 1, characterized in that, The tungsten trioxide in step S1 is tungsten trioxide nanorods.
3. The method for synthesizing cadmium telluride by in-situ growth on the surface of tungsten trioxide as described in claim 1, characterized in that, The cadmium source in step S2 is cadmium chloride.
4. The method for synthesizing cadmium telluride by in-situ growth on the surface of tungsten trioxide as described in claim 1, characterized in that, The ultraviolet irradiation time in step S1 is 2-5 minutes.
5. A WO3 / CdTe heterocomposite material prepared by the synthesis method of in-situ growth of cadmium telluride on the surface of tungsten trioxide according to any one of claims 1 to 4.