阅读说明：本技术 一种抗腐蚀的光阳极复合材料及其制备方法 (Corrosion-resistant photo-anode composite material and preparation method thereof ) 是由 俞书宏 刘国强 阳缘 李毅 于 2020-03-19 设计创作，主要内容包括：本发明提供了一种抗腐蚀的光阳极复合材料,由RGO纳米片、CdSe<Sub>1-x</Sub>Te<Sub>x</Sub>纳米线和助催化剂组成；所述CdSe<Sub>1-x</Sub>Te<Sub>x</Sub>纳米线和所述助催化剂分散于所述RGO纳米片表面；本申请还提供了一种抗腐蚀的光阳极复合材料。本发明提供的光阳极复合材料通过引入还原氧化石墨烯作为载流子传输层来增强CdSe<Sub>1-x</Sub>Te<Sub>x</Sub>纳米线与助催化剂之间的空穴输运,进而减少了光生空穴对CdSe<Sub>1-x</Sub>Te<Sub>x</Sub>纳米线的光腐蚀作用,为设计开发具有高稳定性的光阳极纳米材料提供了一条新的途径。(The invention provides an anticorrosive photo-anode composite material, which is prepared from RGO nanosheets and CdSe 1‑x Te x The nanowire and the cocatalyst; the CdSe 1‑x Te x The nanowires and the cocatalyst are dispersed on the surface of the RGO nanosheets; the present application also provides a corrosion resistant photoanode composite. The photoanode composite material provided by the invention enhances CdSe by introducing reduced graphene oxide as a carrier transport layer 1‑x Te x Hole transport between the nanowire and the cocatalyst, thereby reducing the photo-generated hole pair CdSe 1‑x Te x Photo-etching effect of nano-wire, photo-anode nano-wire with high stability for design and developmentThe material provides a new approach.)

1. An anticorrosion composite photoanode material is prepared from RGO nanosheets and CdSe_1-xTe_xThe nanowire and the cocatalyst; the CdSe_1-xTe_xThe nanowires and the cocatalyst are dispersed on the surface of the RGO nanosheets;

wherein x is more than 0 and less than 1.

2. The photoanode composite of claim 1, wherein the promoter is selected from PdS, RuO₂And a CoPi.

3. The photoanode composite material of claim 1, wherein the content of the RGO nanosheets is 0.1 to 5 wt% and the content of the co-catalyst is 0.1 to 1 wt% based on the photoanode composite material.

4. A preparation method of a corrosion-resistant photo-anode composite material comprises the following steps:

A) mixing CdSe_1-xTe_xThe nano-wire is dispersed in a GO-containing solution, and CdSe is obtained by an ultrasonic and hydrothermal method_1-xTe_xa/RGO composite nanomaterial; x is more than 0 and less than 1;

B) the CdSe is added_1-xTe_xthe/RGO composite nano material is dispersed in a solution containing cocatalyst nano particles, and the corrosion-resistant photo-anode composite material is obtained by an ultrasonic and hydrothermal method.

5. The preparation method according to claim 4, wherein the cocatalyst is PdS nanoparticles; the preparation method of the PdS nano-particles comprises the following steps:

mixing a palladium source and a sulfur source in an aqueous solution, and obtaining PdS nano-particles by a hydrothermal method;

the palladium source is selected from one or more of palladium chloride, palladium nitrate, palladium acetate and palladium tetrachloride; the sulfur source is selected from one or more of sulfur powder, thiourea and sodium sulfide.

6. The method of claim 4, wherein the CdSe are introduced into the reaction chamber_1-xTe_xThe nanowires were prepared as follows:

mixing Te_xSe_y@Se_1-x-yMixing and heating the nanowire and the cadmium source in the aqueous solution, and reacting to obtain CdSe_1-xTe_xA nanowire; x is more than 0 and less than 1, and y is more than 0 and less than 1;

the cadmium source is selected from one or more of cadmium chloride, cadmium nitrate tetrahydrate and cadmium acetate.

7. The preparation method according to claim 4, wherein in the step A), the temperature of the hydrothermal reaction is 140-180 ℃, the heating rate is 5-10 ℃/min, and the time is 6-18 h.

8. The method according to claim 4, wherein in step A), the CdSe is prepared_1-xTe_xThe content of the RGO in the/RGO composite nano material is 0.1-2 wt%.

9. The preparation method according to claim 4, wherein in the step B), the temperature of the hydrothermal reaction is 140-180 ℃, the heating rate is 5-10 ℃/min, and the time is 6-18 h; the hydrothermal reaction is carried out in a reaction kettle.

Technical Field

The invention relates to the technical field of nano materials, in particular to a corrosion-resistant photo-anode composite material and a preparation method thereof.

Background

Photoelectrochemical (PEC) hydrogen production provides a promising and sustainable way to address the energy crisis. However, the instability and low energy conversion efficiency of the catalyst affect its role in practical applications. The instability of the photoelectrode is mainly caused by photo-erosion of the semiconductor, and photo-induced generation of electrons (holes) can drive degradation or decomposition of the semiconductor itself in the electrolyte solution. However, the rapid consumption of photo-generated electrons (holes) can effectively suppress the occurrence of photo-etching reaction, while also enhancing the separation efficiency of photo-generated charges.

Of the numerous semiconductor materials, the II-VI semiconductors CdX (X ═ Te and Se) with a band gap of 1.4-1.7eV have strong absorption of visible and near infrared light, suitable band gaps and high absorption cross-section coefficients (α, 10)⁵cm^-1) Making such materials potentially useful as efficient photoelectrodes. However, cadmium chalcogenides (such as CdTe and CdSe) have a very severe photo-etching process, and the photoelectrode is oxidized by photogenerated holes to cause deactivation. For example, the photoetching process of CdSe under illumination is shown in (1): CdSe +2h⁺———Cd²⁺+Se (1)。

In order to suppress the photo-etching process in such a photoelectrode, it is necessary to rapidly consume photo-generated holes or to suppress the occurrence of oxidation reactions in the photoelectrode. At present, the common methods of scientists are to increase the rate of transfer and consumption of photogenerated holes, such as building hetero/homo junctions, introducing promoters and adding hole sacrificants. Furthermore, isolating the semiconductor material from the electrolyte solution by creating a passivation layer is also an effective method to prevent photo-corrosion. Although these methods can significantly improve the stability of photoelectrodes, there are some key issues to be addressed, such as the rate limiting of hole transport in hetero/homo junction or semiconductor/co-catalyst systems and the shielding of the active sites by passivation layers. The presence of these problems inhibits the improvement of the energy conversion efficiency.

Reduced graphene oxide nanoplatelets (RGO) have unique electronic properties, large specific surface area and excellent optical properties and are an irreplaceable component of PEC photoelectrodes. In addition, RGO can be used as an effective electron donor and a good hole extraction layer, which can improve the stability of a semiconductor by increasing the transport ability of photogenerated carriers. However, the efficiency of depletion of photo-generated holes is still particularly low due to the shielding effect caused by RGO. Thus, it is still necessary to provide a photoanode material that is resistant to photo-corrosion.

Disclosure of Invention

The invention aims to provide a photo-anode composite material with photo-corrosion resistance.

In view of the above, the present application provides a corrosion-resistant photo-anode composite material, which is prepared from RGO nanosheets and CdSe_1-xTe_xThe nanowire and the cocatalyst; the CdSe_1-xTe_xThe nanowires and the cocatalyst are dispersed on the surface of the RGO nanosheets;

wherein x is more than 0 and less than 1.

Preferably, the cocatalyst is selected from PdS, RuO₂And a CoPi.

Preferably, the photoanode composite material is used as a base, the content of the RGO nanosheet is 0.1-5 wt%, and the content of the cocatalyst is 0.1-1 wt%.

The application also provides a preparation method of the corrosion-resistant photo-anode composite material, which comprises the following steps:

A) mixing CdSe_1-xTe_xThe nano-wire is dispersed in a GO-containing solution, and CdSe is obtained by an ultrasonic and hydrothermal method_1-xTe_xa/RGO composite nanomaterial; x is more than 0 and less than 1;

B) the CdSe is added_1-xTe_xthe/RGO composite nano material is dispersed in a solution containing cocatalyst nano particles, and the corrosion-resistant photo-anode composite material is obtained by an ultrasonic and hydrothermal method.

Preferably, the cocatalyst is PdS nanoparticles; the preparation method of the PdS nano-particles comprises the following steps:

mixing a palladium source and a sulfur source in an aqueous solution, and obtaining PdS nano-particles by a hydrothermal method;

the palladium source is selected from one or more of palladium chloride, palladium nitrate, palladium acetate and palladium tetrachloride; the sulfur source is selected from one or more of sulfur powder, thiourea and sodium sulfide.

Preferably, the CdSe_1-xTe_xThe nanowires were prepared as follows：

Mixing Te_xSe_y@Se_1-x-yMixing and heating the nanowire and the cadmium source in the aqueous solution, and reacting to obtain CdSe_1-xTe_xA nanowire; x is more than 0 and less than 1, and y is more than 0 and less than 1;

the cadmium source is selected from one or more of cadmium chloride, cadmium nitrate tetrahydrate and cadmium acetate.

Preferably, in the step A), the temperature of the hydrothermal reaction is 140-180 ℃, the heating rate is 5-10 ℃/min, and the time is 6-18 h.

Preferably, in step A), the CdSe_1-xTe_xThe content of the RGO in the/RGO composite nano material is 0.1-2 wt%.

Preferably, in the step B), the temperature of the hydrothermal reaction is 140-180 ℃, the heating rate is 5-10 ℃/min, and the time is 6-18 h; the hydrothermal reaction is carried out in a reaction kettle.

The application provides a corrosion-resistant photo-anode composite material which is prepared from RGO nanosheets and CdSe_1-xTe_xThe nanowire and the cocatalyst; the CdSe_1-xTe_xNanowires and the co-catalyst are dispersed on the surface of the RGO nanoplates. The light anode composite material provided by the application combines the hole transmission capability of RGO and the hole extraction layer formed by the cocatalyst on the hole consumption capability, so that the composite material can realize the rapid consumption and separation of the holes, finally has the light corrosion resistance characteristic, and improves the energy conversion efficiency of the photoelectrode.

Drawings

FIG. 1 shows TexSe prepared in example 1 of the present invention_y@Se_1-x-yA nanowire Transmission Electron Microscope (TEM) image;

FIG. 2 shows CdSe prepared according to example 1 of the present invention_1-xTe_x(CST) nanowire TEM images;

FIG. 3 is a TEM image and a powder X-ray spectrum (XRD) of PdS nanoparticles prepared in example 2 of the present invention;

FIG. 4 shows CdSe prepared in examples 3-4 of the present invention_1-xTe_x/RGO (CST/RGO) and CdSe_1-xTe_x/RGO/PdS(CST/RGO/PdS) TEM images of the composite nanomaterials;

FIG. 5 shows CdSe prepared in examples 3-4 of the present invention_1-xTe_x/RGO (CST/RGO) and CdSe_1-xTe_xScanning Electron Microscope (SEM) images of/RGO/PdS (CST/RGO/PdS) composite nanomaterials;

FIG. 6 shows CdSe prepared in examples 1-4 of the present invention_1-xTe_x(CST) nanowire, CdSe_1-xTe_x/RGO (CST/RGO) and CdSe_1-xTe_xPowder X-ray spectra of/RGO/PdS (CST/RGO/PdS) composite nanomaterials;

FIG. 7 shows CdSe prepared in example 4 of the present invention_1-xTe_xHigh resolution transmission electron microscope images of/RGO/PdS (CST/RGO/PdS) composite nanomaterials;

FIG. 8 shows CdSe prepared according to example 1 of the present invention_1-xTe_x(CST) EDS elemental plane distribution image of nanowires;

FIG. 9 shows CdSe prepared in example 3 of the present invention_1-xTe_xEDS element plane distribution image of/RGO (CST/RGO) composite nano material;

FIG. 10 shows CdSe prepared in example 4 of the present invention_1-xTe_xEDS element plane distribution image of/RGO/PdS (CST/RGO/PdS) composite nano material;

FIG. 11 shows CdSe prepared in examples 1-4 of the present invention_1-xTe_x(CST) nanowire, CdSe_1-xTe_x/RGO (CST/RGO) and CdSe_1-xTe_xUV-vis absorption spectra of/RGO/PdS (CST/RGO/PdS) composite nanomaterials;

FIG. 12 shows CdSe prepared in examples 1-4 of the present invention_1-xTe_x(CST) nanowire, CdSe_1-xTe_x/RGO (CST/RGO) and CdSe_1-xTe_xCurrent-voltage, current-time, and amperage-time maps of/RGO/PdS (CST/RGO/PdS).

Detailed Description

For a further understanding of the invention, reference will now be made to the preferred embodiments of the invention by way of example, and it is to be understood that the description is intended to further illustrate features and advantages of the invention, and not to limit the scope of the claims.

Based on the problem of photo-corrosion resistance of the photo-anode material, the application provides a photo-anode composite material which realizes the rapid decomposition and consumption of photo-generated holes in a photo-electrode and improves the energy conversion efficiency. Specifically, the embodiment of the invention discloses an anti-corrosion photo-anode composite material which is prepared from RGO nanosheets and CdSe_1-xTe_xThe nanowire and the cocatalyst; the CdSe_1-xTe_xThe nanowires and the cocatalyst are dispersed on the surface of the RGO nanosheets;

wherein x is more than 0 and less than 1.

In the photoanode composite material provided by the application, the CdSe_1-xTe_xThe nano-wire and the cocatalyst are uniformly dispersed on the surface of the RGO nano-sheet, and the CdSe_1-xTe_xThe nanowires and the promoter do not differ significantly in position. In the present application, the promoter is in particular an oxidation promoter, chosen from PdS, RuO₂And CoPi, in particular embodiments, the promoter is a PdS nanoparticle.

In the photoanode composite material, the photoanode composite material is taken as a base, the content of the RGO nanosheet is 0.1-5 wt%, and the content of the cocatalyst is 0.1-1 wt%.

The application also provides a preparation method of the corrosion-resistant photo-anode composite material, which comprises the following steps:

A) mixing CdSe_1-xTe_xThe nano-wire is dispersed in a GO-containing solution, and CdSe is obtained by an ultrasonic and hydrothermal method_1-xTe_xa/RGO composite nanomaterial; x is more than 0 and less than 1;

B) mixing CdSe_1-xTe_xthe/RGO composite nano material is dispersed in a solution containing cocatalyst nano particles, and the corrosion-resistant photo-anode composite material is obtained by an ultrasonic and hydrothermal method.

The sources of all raw materials are not particularly limited in the invention, and the raw materials can be either commercially available or self-made.

Wherein, the CdSe_1-xTe_xThe nanowire has x greater than zero and less than 1, specifically, x can be selected from 0.33, 0.20, 0.14, 0.11, 0.08, and 0.06, and in some embodiments provided by the present invention, x is preferably 0.14.

In the present invention, the CdSe_1-xTe_xThe nano-wire is prepared by a hydrothermal synthesis method; i.e. with Te_xSe_y@Se_1-x-yThe nano wire is a hard template, and the cadmium source and Te are reacted at a certain reaction temperature_xSe_y@Se_1-x-yNanowire reaction to obtain CdSe_1-xTe_xA nanowire; the preparation method specifically comprises the following steps:

mixing Te_xSe_y@Se_1-x-yMixing and heating the nanowire and a cadmium source in an aqueous solution to react to obtain CdSe_1-xTe_xA nanowire; the cadmium source is preferably a cadmium salt, and more preferably one or more of cadmium chloride, cadmium nitrate tetrahydrate and cadmium acetate; the temperature of the mixing and heating reaction is preferably 140-180 ℃, more preferably 160-180 ℃, and further preferably 160 ℃; the heating rate is preferably 5-10 ℃/min, more preferably 8-10 ℃/min, and most preferably 9 ℃/min; the mixing and heating reaction time is preferably 6-18 h, and more preferably 10-12 h. In the above Te_xSe_y@Se_1-x-yIn the nanowires, x is greater than zero and less than 1, and the value of y represents the amount of Se element forming an alloy phase with Te element in the nanowires of the core-shell structure, and although the value cannot be specifically determined, the value thereof is greater than zero and less than 1; in specific values, x can be selected from 0.33, 0.20, 0.14, 0.11, 0.08 and 0.06; in a particular embodiment, said x is preferably 0.14.

The CdSe_1-xTe_xThe preparation of the nano-wire is more specifically as follows: reacting TexSe_y@Se_1-x-yMixing and heating the nanowire and the cadmium source in an aqueous solution until the reaction temperature is kept at 140-180 ℃, preferably 160-180 ℃, and further preferably 160 ℃; the heating reaction time is preferably 6-18 h, and more preferably 10-12 h; after the reaction is finished, cooling. The cooling method is well known to those skilled in the art, and is not particularly limited in the following embodimentsNatural cooling is adopted in the embodiment; after cooling, the CdSe is obtained by centrifugation and washing_1-xTe_xA nanowire; the washing is preferably carried out with hexane and ethanol.

The application then combines the CdSe with a binder_1-xTe_xThe nanowire is compounded with RGO to obtain CdSe_1-xTe_xa/RGO composite nanomaterial; the CdSe_1-xTe_xThe synthesis method of the/RGO composite nano material is preferably an ultrasonic method and a hydrothermal method, and specifically comprises the following steps:

mixing CdSe_1-xTe_xMixing the nanowire with GO, and then obtaining CdSe through ultrasound and hydrothermal treatment_1-xTe_xthe/RGO composite nano material.

During the above preparation, the GO is preferably added in the form of an aqueous GO solution; the concentration of GO in the GO water solution is preferably 0.1-0.5 mg/ml, more preferably 0.2-0.4 mg/ml, and still more preferably 0.35 mg/ml; in the present invention, CdSe is preferably first introduced_1-xTe_xThe nano-wires are dispersed in the water solution and then mixed with the chloroauric acid solution; the CdSe_1-xTe_xAnd promoting CdSe under ultrasound after GO is mixed_1-xTe_xCompounding with GO; the ultrasonic treatment time is preferably 10-60 min, more preferably 20-50 min, and most preferably 30 min; the temperature of the mixing and heating reaction is preferably 140-180 ℃, more preferably 160-180 ℃, and further preferably 180 ℃; the heating rate is preferably 5-10 ℃/min, more preferably 8-10 ℃/min, and most preferably 9 ℃/min; the mixing and heating reaction time is preferably 6-18 h, and more preferably 10-12 h; after the reaction is finished, the product is precipitated, centrifuged and washed by ethanol to obtain CdSe_1-xTe_xa/RGO composite nanomaterial; the washing is preferably with ethanol. The CdSe_1-xTe_xThe mass fraction of RGO in the/RGO composite nano material is preferably 0.1-5%, more preferably 0.1-3%, still more preferably 0.1-2%, and most preferably 0.1-1.5%.

In the invention, the cocatalyst is specifically an oxidation cocatalyst and can be selected from PdS nanoparticles and RuO₂One or more of nanoparticles and CoPi nanoparticles, in particular embodiments,the cocatalyst is selected from PdS nanoparticles, and the PdS nanoparticles are preferably prepared according to the following method: mixing a palladium source and a sulfur source in an aqueous solution, and obtaining PdS nano-particles by a hydrothermal method; the palladium source is preferably one or more of palladium chloride, palladium nitrate, palladium acetate and palladium tetrachloride; the sulfur source is preferably one or more of sulfur powder, thiourea and sodium sulfide; the temperature of the mixing and heating reaction is preferably 150-180 ℃, more preferably 160-180 ℃, and further preferably 160 ℃; the heating rate is preferably 5-10 ℃/min, more preferably 8-10 ℃/min, and most preferably 9 ℃/min; the mixing and heating reaction time is preferably 6-18 h, and more preferably 10-12 h. In a specific embodiment, the reaction is more specifically: mixing and heating palladium tetrachloride and sulfur powder in an aqueous solution until the reaction temperature is kept at 140-180 ℃, preferably 160-180 ℃, and then preferably 160 ℃; the heating reaction time is preferably 6-18 h, and more preferably 10-12 h. After the reaction is finished, cooling; the cooling method is not particularly limited, and natural cooling is preferable in the present invention; after cooling, preferably centrifuging and washing to obtain PdS nano particles; the washing is preferably carried out with ultrapure water or ethanol.

The last application will be said of CdSe_1-xTe_xRespectively dispersing the/RGO composite nano material and the PdS nano particles in an aqueous solution, mixing the two dispersed solutions after dispersion, stirring and heating for reaction; the temperature of the mixing and heating reaction is preferably 140-180 ℃, more preferably 160-180 ℃, and further preferably 180 ℃; the heating rate is preferably 5-10 ℃/min, more preferably 8-10 ℃/min, and most preferably 9 ℃/min; the mixing and heating reaction time is preferably 6-18 h, and more preferably 10-12 h. After the heating reaction is finished, the product is preferably precipitated, centrifuged and washed by ethanol to obtain CdSe_1-xTe_xa/RGO/PdS composite nanomaterial; the washing is preferably carried out with ultrapure water or ethanol.

In the above process, CdSe is used_1-xTe_xBased on the/RGO composite nano material, PdS nano particles are further compounded on the RGO nano sheet to obtain CdSe_1-xTe_xthe/RGO/PdS composite nano material. The CdSe_1-xTe_xThe mass fraction of RGO in the/RGO/PdS composite nano material is 0.1-5%, more preferably 0.1-3%, still more preferably 0.1-2%, and most preferably 0.1-1.5%; the mass fraction of PdS is 0.1-1%, more preferably 0.1-0.8%, and most preferably 0.1-0.5%;

the photoanode composite material provided by the invention enhances CdSe by introducing reduced graphene oxide as a carrier transport layer_1-xTe_xHole transport between the nanowire and the cocatalyst, thereby reducing the photo-generated hole pair CdSe_1-xTe_xThe photo-etching effect of the nano-wire provides a new approach for designing and developing photo-anode nano-materials with high stability.

For further understanding of the present invention, the following examples are given to illustrate the corrosion-resistant photoanode composite material provided by the present invention, and the scope of the present invention is not limited by the following examples.

The reagents used in the following examples are all commercially available.