阅读说明：本技术 一种氮化碳-Pd纳米粒子材料及其制备方法和应用 (Carbon nitride-Pd nano particle material and preparation method and application thereof ) 是由 蒋保江 肖旭东 林斯颖 李琪 付宏刚 于 2021-09-23 设计创作，主要内容包括：一种氮化碳-Pd纳米粒子材料及其制备方法和应用,属于分解水析氢材料技术领域。本发明氮化碳-Pd纳米粒子材料是通过三聚氰胺和亚磷酸自组装和高温煅烧方法合成氮化碳,再以搅拌和煅烧的方法在氮化碳上生长Pd纳米粒子得到的。氮化碳-Pd纳米粒子材料为中空管状结构。本发明还提供了氮化碳-Pd纳米粒子材料的制备方法及其在催化水解产氢中的应用。本发明制备的氮化碳-Pd纳米粒子结构具有独特的分级结构,具有独特的中空管状结构。制备方法简单易操作,成本低。(A carbon nitride-Pd nano particle material and a preparation method and application thereof, belonging to the technical field of water-decomposing hydrogen evolution materials. The carbon nitride-Pd nano particle material is obtained by synthesizing carbon nitride through self-assembly of melamine and phosphorous acid and high-temperature calcination, and then growing Pd nano particles on the carbon nitride through stirring and calcination. The carbon nitride-Pd nano particle material is of a hollow tubular structure. The invention also provides a preparation method of the carbon nitride-Pd nano particle material and application of the carbon nitride-Pd nano particle material in hydrogen production by catalytic hydrolysis. The carbon nitride-Pd nano particle structure prepared by the method has a unique hierarchical structure and a unique hollow tubular structure. The preparation method is simple and easy to operate and has low cost.)

1. The carbon nitride-Pd nano particle material is characterized in that the carbon nitride-Pd nano particle material is obtained by synthesizing carbon nitride through a self-assembly and high-temperature calcination method of melamine and phosphorous acid, and then growing Pd nano particles on the carbon nitride through a stirring and calcination method.

2. A carbon nitride-Pd nanoparticle material according to claim 1, wherein said carbon nitride-Pd nanoparticle material has a hollow tubular structure.

3. The carbon nitride-Pd nanoparticle material according to claim 1, wherein the molar concentration of melamine and solid phosphorous acid is 1: 0.8-1.2.

4. A carbon nitride-Pd nanoparticle material, characterized by the steps of:

(1) adding melamine while stirring distilled water at 40-90 ℃, adding solid phosphorous acid after stirring for 30-90min, and continuing stirring for 15-90 min;

(2) transferring to a reaction kettle, heating in an oven, centrifuging, and drying the obtained precipitate to obtain a precursor;

(3) weighing the precursor obtained in the step (2), placing the precursor in a tubular furnace, and calcining the precursor in a nitrogen atmosphere to obtain a product tubular carbon nitride;

(4) dispersing the TCN obtained in the step (3) in PdCl₂Stirring for 4-10h at room temperature in an aqueous solution of thiourea amidinate;

(5) washing with deionized water for several times, drying in a drying oven for 4-8h, transferring to a tubular furnace, and calcining in nitrogen atmosphere to obtain the carbon nitride-Pd nanoparticles.

5. The method according to claim 4, wherein the molar concentration of the melamine and the solid phosphorous acid added in the step (1) is 1: 0.8-1.2.

6. The method according to claim 4, wherein the heating treatment in the step (2) is carried out under the conditions: the heating temperature is 150-; the centrifugation conditions were: the rotating speed is 2000-; the drying conditions were: the drying temperature is 40-80 ℃, and the drying time is 6-12 h.

7. The method according to claim 4, wherein the calcining in the step (3) is carried out under the conditions of: the calcination temperature is 500-600 ℃, and the calcination time is 1-2 h.

8. The method according to claim 4, wherein the PdCl in step (4) is PdCl₂The volume-mass ratio of the guanyl thiourea aqueous solution to the precursor weighed in the step (3) is 50-100:1mL/g, and the PdCl is₂PdCl in aqueous solution of thiourea amidinate₂The mass fraction of the PdCl is 0.17-0.5mg/mL₂PdCl in aqueous solution of thiourea amidinate₂The molar ratio to amidinothiourea was 1: 4.

9. The method according to claim 4, wherein the calcining in the step (5) is carried out under the conditions of: the initial temperature is room temperature, and the heating rate is 2-5 deg.C for min^-1Heating to 150-200 ℃, keeping the temperature and continuing calcining for 1-2 h.

10. Use of a carbon nitride-Pd nanoparticle material according to any one of claims 1-3 in the catalytic hydrolysis to produce hydrogen.

Technical Field

The invention belongs to the technical field of materials for decomposing water and evolving hydrogen, and particularly relates to a carbon nitride-Pd nanoparticle material and a preparation method and application thereof.

Background

The formation of chemical bonds between metal ions and their supports has proven to be an effective strategy for achieving good catalytic activity. However, the synthesis of active metal species on a support and control of their coordination environment remains challenging. Here we show the use of organic compounds to produce Tubular Carbon Nitride (TCN) as a support for Pd Nanoparticles (NPs), creating a composite material, carbon nitride-Pd nanoparticle material (NP-Pd-TCN). It was found that Pd ions preferentially bind to the electron-rich N atom of TCN, resulting in strong metal-carrier interactions favoring charge transfer from g-C₃N₄Transfer to Pd. X-ray absorption spectroscopy further revealed that metal-support interactions lead to the formation of Pd-N bonds, which are responsible for the improved charge kinetics, as evidenced by the results of various techniques such as Photoluminescence (PL) spectroscopy, photocurrent measurements, and Electrochemical Impedance Spectroscopy (EIS). Because of the good dynamic performance, NP-Pd-TCN is used for photocatalytic hydrogen evolution under the irradiation of visible light, and 381 mu mol h is obtained^-1(0.02g photocatalyst) high hydrogen evolution rate. This work is directed to strategies to promote the synthesis of efficient hydrogen production photocatalysts by controllably introducing metal nanoparticles onto a support and simultaneously forming chemical bonds to achieve intimate metal-to-support contact.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to design and provide a carbon nitride-Pd nanoparticle material, and a preparation method and application thereof. The carbon nitride-Pd nano particle material is prepared by synthesizing TCN with a hollow hexagonal tube structure by a melamine and phosphorous acid self-assembly and high-temperature calcination method, and then growing Pd nano particles on the TCN by a stirring and calcination method. The material has good water decomposition and hydrogen evolution performance and good stability, and the method is simple and easy to operate and has low cost.

In order to achieve the purpose, the invention adopts the following technical scheme:

the carbon nitride-Pd nano particle material is characterized in that the carbon nitride-Pd nano particle material is obtained by synthesizing carbon nitride through a self-assembly and high-temperature calcination method of melamine and phosphorous acid, and then growing Pd nano particles on the carbon nitride through a stirring and calcination method.

The carbon nitride-Pd nano particle material is characterized in that the carbon nitride-Pd nano particle material is of a hollow tubular structure.

The carbon nitride-Pd nano particle material is characterized in that the molar concentration of melamine and solid phosphorous acid is 1: 0.8-1.2.

A carbon nitride-Pd nanoparticle material, characterized by the steps of:

(1) adding melamine while stirring distilled water at 40-90 ℃, adding solid phosphorous acid after stirring for 30-90min, and continuing stirring for 15-90 min;

(2) transferring to a reaction kettle, heating in an oven, centrifuging, and drying the obtained precipitate to obtain a precursor;

(3) weighing the precursor obtained in the step (2), placing the precursor in a tubular furnace, and calcining the precursor in a nitrogen atmosphere to obtain a product tubular carbon nitride;

(4) dispersing the TCN obtained in the step (3) in PdCl₂Stirring for 4-10h at room temperature in an aqueous solution of thiourea amidinate;

(5) washing with deionized water for several times, drying in a drying oven for 4-8h, transferring to a tubular furnace, and calcining in nitrogen atmosphere to obtain the carbon nitride-Pd nanoparticles.

The preparation method is characterized in that the molar concentration of the melamine and the solid phosphorous acid added in the step (1) is 1: 0.8-1.2.

The preparation method is characterized in that the heating treatment conditions in the step (2) are as follows: the heating temperature is 150-; the centrifugation conditions were: the rotating speed is 2000-; the drying conditions were: the drying temperature is 40-80 ℃, and the drying time is 6-12 h.

The preparation method is characterized in that the calcining conditions in the step (3) are as follows: the calcination temperature is 500-600 ℃, and the calcination time is 1-2 h.

The preparation methodA process characterized in that PdCl in said step (4)₂The volume-mass ratio of the guanyl thiourea aqueous solution to the precursor weighed in the step (3) is 50-100:1mL/g, and the PdCl is₂PdCl in aqueous solution of thiourea amidinate₂The mass fraction of the PdCl is 0.17-0.5mg/mL₂PdCl in aqueous solution of thiourea amidinate₂The molar ratio to amidinothiourea was 1: 4.

The preparation method is characterized in that the calcining conditions in the step (5) are as follows: the initial temperature is room temperature, and the heating rate is 2-5 deg.C for min^-1Heating to 150-200 ℃, keeping the temperature and continuing calcining for 1-2 h.

The application of any one of the carbon nitride-Pd nano particle materials in hydrogen production by catalytic hydrolysis.

Compared with the prior art, the invention has the remarkable effects as follows:

1) the NP-Pd-TCN structure prepared by the invention has a unique hierarchical structure and a unique hollow tubular structure.

2) The synthetic method is simple and easy to operate and low in cost. The synthesized NP-Pd-TCN structure has excellent water-splitting and hydrogen-evolution performances.

Drawings

FIG. 1 is a scanning electron microscope image of the supramolecular precursor obtained in example 1;

FIG. 2 is a scanning electron microscope image of the NP-Pd-TCN nanomaterial obtained in example 1;

FIG. 3 is a scanning electron microscope image of the NP-Pd-TCN nanomaterial obtained in example 2;

FIG. 4 is a TEM image of the NP-Pd-TCN nanomaterial obtained in example 2;

FIG. 5 is a scanning electron microscope image and a transmission electron microscope image of the NP-Pd-TCN nanomaterial obtained in example 3.

Detailed Description

The present invention will be described in further detail with reference to the following detailed description and accompanying drawings.

Example 1:

the method for preparing the NP-Pd-TCN structure for photocatalytic hydrogen production by using the hydrothermal method comprises the following steps:

1) under the condition of stirring at 80 ℃, 1g of melamine is added into distilled water, 1.2g of solid phosphorous acid is added after stirring for 60min, and stirring is continued for 60 min;

2) transferring the solution obtained in the step 1) into a reaction kettle, and heating in an oven at 180 ℃ for 10 hours;

3) centrifuging the product obtained in the step 2), wherein the rotating speed is 4000r/min, and the centrifuging time is 3 min;

4) drying the product obtained in the step 3) in a drying oven at the drying temperature of 60 ℃ for 10h to obtain a precursor;

5) putting the precursor (1.0g) obtained in the step 4) into a tubular furnace, and calcining at 600 ℃ in a nitrogen atmosphere for 1.5 h;

6) dispersing the product TCN obtained in the step 5) in 100mL of PdCl₂Aqueous solution of thiourea amidinate (17mg PdCl)₂) Stirring for 10 hours at room temperature;

7) transferring the solution obtained in the step 6) into a reaction kettle, and heating in an oven at the heating temperature of 120 ℃ for 10 hours.

8) The product obtained in step 7) was put in a tube furnace under nitrogen at 200 ℃ (heating rate of 2.5 ℃ for min^-1) Then calcining for 1 hour to obtain the product named NP-Pd-TCN.

Fig. 1 is a scanning electron microscope image of a precursor obtained by self-assembly of melamine and solid phosphorous acid, which can be seen to have a hollow tubular structure. The SEM image of NP-Pd-TCN obtained in this example is shown in FIG. 2.

Example 2:

the method for preparing the NP-Pd-TCN structure for photocatalytic hydrogen production by using the hydrothermal method comprises the following steps:

1) under the condition of stirring at 80 ℃, 1g of melamine is added into distilled water, 1.2g of solid phosphorous acid is added after stirring for 60min, and stirring is continued for 60 min;

2) transferring the solution obtained in the step 1) into a reaction kettle, and heating in an oven at 180 ℃ for 10 hours;

3) centrifuging the product obtained in the step 2), wherein the rotating speed is 4000r/min, and the centrifuging time is 3 min;

4) drying the product obtained in the step 3) in a drying oven at the drying temperature of 60 ℃ for 10h to obtain a precursor;

5) putting the precursor (1.0g) obtained in the step 4) into a tubular furnace, and calcining at 600 ℃ in a nitrogen atmosphere for 1.5 h;

6) dispersing the product TCN obtained in step 5) in 100ml of Pdcl₂In aqueous solution of thiosemicarbazide (30mg of PdCl)₂) Stirring for 10 hours at room temperature;

7) transferring the solution obtained in the step 6) into a reaction kettle, and heating in an oven at the heating temperature of 120 ℃ for 10 hours.

8) The product obtained in step 7) was put in a tube furnace under nitrogen at 200 ℃ (heating rate of 2.5 ℃ for min^-1) Then calcining for 1 hour to obtain the product named NP-Pd-TCN.

FIGS. 3 and 4 are scanning electron microscope and transmission electron microscope, respectively, of the NP-Pd-TCN material obtained in this example, which facilitates enhanced separation of photo-generated charges.

Example 3:

the method for preparing the CN-LDH heterostructure for photocatalytic hydrogen production by a hydrothermal method in the embodiment specifically comprises the following steps:

1) under the condition of stirring at 80 ℃, 1g of melamine is added into distilled water, 1.2g of solid phosphorous acid is added after stirring for 60min, and stirring is continued for 60 min;

2) transferring the solution obtained in the step 1) into a reaction kettle, and heating in an oven at 180 ℃ for 10 h. (ii) a

3) Centrifuging the product obtained in the step 2), wherein the rotating speed is 4000r/min, and the centrifuging time is 3 min;

4) drying the product obtained in the step 3) in a drying oven at the drying temperature of 60 ℃ for 10h to obtain a precursor;

5) putting the precursor (1.0g) obtained in the step 4) into a tubular furnace, and calcining at 600 ℃ in a nitrogen atmosphere for 1.5 h;

6) dispersing the product TCN obtained in step 5) in 100ml of Pdcl₂In aqueous solution of thiosemicarbazide (50mg of PdCl)₂) Stirring for 10 hours at room temperature;

7) transferring the solution obtained in the step 6) into a reaction kettle, and heating in an oven at the heating temperature of 120 ℃ for 10 hours.

8) The product obtained in step 7) was put in a tube furnace under nitrogen at 200 ℃ (heating rate of 2.5 ℃ for min^-1) Then calcining for 1 hour to obtain the product named NP-Pd-TCN.

FIG. 5 is a scanning and transmission electron microscope image of the NP-Pd-TCN material obtained in the present example, wherein FIG. 5a is an SEM image of NP-Pd-TCN, FIG. 5b is a TEM image of NP-Pd-TCN, FIG. 5c is an enlarged TEM image corresponding to the labeled region in the FIG. 5b, and FIG. 5d is an enlarged HRTEM image of the label of NP-Pd-TCN in FIG. 5 c. It can be seen from the figure that the distribution of Pd metal particles on the surface of the TCN tube constitutes a close interaction.