Carbon-supported palladium tin tantalum nitride nano electro-catalyst for direct ethanol and methanol fuel cell and preparation method thereof
阅读说明：本技术 用于直接乙醇和甲醇燃料电池的碳载钯锡氮化钽纳米电催化剂及其制备方法 (Carbon-supported palladium tin tantalum nitride nano electro-catalyst for direct ethanol and methanol fuel cell and preparation method thereof ) 是由 姜召 野娜 于 2021-08-17 设计创作，主要内容包括：本发明公开了一种用于直接乙醇和甲醇燃料电池的碳载钯锡氮化钽纳米电催化剂及其制备方法,该催化剂由钯、锡、氮化钽、导电炭黑组成,其制备方法为在碱性乙二醇溶液中制备分散的碳载PdSn@TaN/C纳米电催化剂。本发明为首次制备合成导电炭黑负载氮化钽钯锡电催化剂,制备方法条件温和,操作简单可控,节能环保,具有良好的应用前景。本发明的电催化剂首次使用作为直接乙醇和甲醇燃料电池阳极材料,与商业催化剂(负载量为10％)相比,在贵金属用量(2.86％)显著降低的同时、依然对碱性条件下乙醇和甲醇的氧化反应具有极高电催化活性分别为商业钯碳催化活性的26.9倍和15.6倍)、以及强抗CO中毒能力等优点,具有良好的应用前景。(The invention discloses a carbon-supported palladium tin tantalum nitride nano electro-catalyst for direct ethanol and methanol fuel cells and a preparation method thereof. The invention is a method for preparing the conductive carbon black loaded tantalum palladium tin nitride electrocatalyst for the first time, and the preparation method has mild conditions, simple and controllable operation, energy conservation and environmental protection and good application prospect. Compared with a commercial catalyst (the load is 10%), the electrocatalyst provided by the invention is used as the anode material of a direct ethanol and methanol fuel cell for the first time, has the advantages that the consumption of noble metals (2.86%) is obviously reduced, the extremely high electrocatalytic activity of the electrocatalyst on the oxidation reaction of ethanol and methanol under an alkaline condition is respectively 26.9 times and 15.6 times of that of commercial palladium-carbon, the electrocatalyst has strong CO poisoning resistance, and the like, and has a good application prospect.)
1. A palladium-tin-tantalum nitride on carbon nano electrocatalyst for direct ethanol and methanol fuel cells, characterized by: the catalyst is a core-shell type catalyst with palladium tin tantalum nitride as a shell and carbon as a core, and the molecular formula is PdSn-TaN/C; the mass percentages of the components of palladium, tin, tantalum nitride and conductive carbon black in the catalyst are respectively 2-10%, 2-15%, 15-70% and 15-70%.
2. The palladium-on-carbon tin tantalum nitride nanoelectrocatalyst for direct ethanol and methanol fuel cells according to claim 1, wherein: the palladium tin tantalum nitride is uniformly dispersed on the surface of the carrier conductive carbon black, the average particle diameter of the catalyst is 2-3nm, and the oxidation peak current intensities of ethanol and methanol are 13025.84 and 3293.46A g respectivelyPd -1The method has extremely excellent electrocatalytic oxidation performance of ethanol and methanol under alkaline conditions.
3. The method for preparing the palladium-tin-tantalum nitride-on-carbon nano electrocatalyst for a direct ethanol and methanol fuel cell according to claim 1 or 2, characterized by comprising the following steps:
1) adding tantalum nitride, conductive carbon black and ethylene glycol into a container, placing the container on a magnetic stirrer for stirring, and then carrying out ultrasonic treatment to uniformly disperse the tantalum nitride and the conductive carbon black in the ethylene glycol to obtain a mixture A;
2) adding sodium chloropalladate, stannous chloride, sodium citrate and potassium hydroxide solution into the mixture A obtained in the step 1), and uniformly stirring the mixture A on a magnetic stirrer to obtain a mixture B, wherein the sodium chloropalladate with the corresponding mass is added according to the mass percent of 2-10% of palladium loading capacity, the stannous chloride with the corresponding mass is added according to the mass percent of 2-15% of tin loading capacity, the potassium hydroxide is added according to 5-30 times of the mass of the sodium chloropalladate, and the reducing agent sodium citrate is added according to 8-10 times of the mass of the sodium chloropalladate;
3) heating the mixture B obtained in the step 2) to 100-130 ℃, stirring for 1-6h, wherein sodium chloropalladate and stannous chloride are respectively reduced into metal palladium and tin to obtain a solid-liquid mixture, and then cooling to room temperature;
4) and washing the solid-liquid mixture cooled to room temperature with deionized water and absolute ethyl alcohol until no ethylene glycol, ammonium ions and chloride ions remain, drying in an oven at the temperature of 60-80 ℃ for 6-12 h, and grinding to obtain the carbon-supported palladium tin tantalum nitride nano electro-catalyst for the direct ethyl alcohol and methanol fuel cell.
4. The method of claim 3, wherein: the mass ratio of the tantalum nitride to the conductive carbon black in the step (1) is 0.5-3: 1, and the tantalum nitride and the ethylene glycol correspond to 1mL of ethylene glycol per 4mg of tantalum nitride.
5. The method of claim 3, wherein: stirring time on the magnetic stirrer in the step (1) is 15-30 min, and ultrasonic treatment time in the step (1) is 60-120 min.
6. The use of the palladium on carbon tin tantalum nitride nanoelectrocatalyst according to claim 1, wherein: the catalyst is used as an anode electrocatalyst for direct ethanol and methanol fuel cells under alkaline conditions.
Technical Field
The invention belongs to the technical field of fuel cell electrocatalysts, and particularly relates to a carbon-supported palladium-tin-tantalum nitride nano electrocatalyst for a direct ethanol and methanol fuel cell and a preparation method thereof.
Background
In recent years, development of new renewable energy sources to replace conventional fossil fuels (coal, petroleum, etc.) has received much attention. Fuel cells provide a sustainable opportunity for the development of next generation clean energy devices as a promising alternative system. New clean energy sources typically include hydrogen and small carbon-containing molecules (typically ethanol or methanol) as fuel cell molecules. Among them, the direct ethanol and methanol fuel cells convert chemical energy (alcohol fuel) stored in fuel into electric energy.
They have the characteristics of high theoretical specific energy density, rich fuel sources, low price, environmental friendliness and the like. For fuel cells, the catalyst is the core of the fuel cell.
Research shows that the noble metal palladium (Pd) is an effective catalyst for the oxidation reaction of ethanol and methanol in an alkaline medium. However, considering that it is a noble metal and is easily poisoned by carbon monoxide, it is necessary to further improve the catalytic activity and stability of the palladium catalyst for the purpose of high efficiency and low cost to meet the large-scale commercialization demand of the fuel cell. Therefore, it is necessary to develop a catalyst with high catalytic activity, stability and low cost, but so far, no relevant documents and patent reports are found for the research on the carbon-supported palladium tin tantalum nitride nano electrocatalyst of the direct ethanol and methanol fuel cell.
The key factors for restricting the direct ethanol and methanol fuel cells at present are how to design and develop a catalyst which simultaneously has high electrocatalytic activity, strong CO poisoning resistance and low noble metal consumption, thereby promoting the large-scale application of the direct ethanol and methanol fuel cells.
Disclosure of Invention
In order to solve the bottleneck of the prior art, the invention aims to provide the carbon-supported palladium-tin-tantalum nitride nano electrocatalyst for the direct ethanol and methanol fuel cell and the preparation method thereof. The electrocatalyst is also used as the anode material of the direct ethanol and methanol fuel cell for the first time, and the electro-oxidation of ethanol and methanol under alkaline conditions reduces the consumption of noble metals, and still has the advantages of high electro-catalytic activity, strong CO poisoning resistance and the like through the synergistic effect of tin and tantalum nitride, thereby reducing the cost of the catalyst, improving the efficiency of the fuel cell and the utilization rate of the noble metals, and accelerating the process of commercial application of the catalyst.
In order to achieve the purpose, the invention adopts the following technical scheme:
a carbon-supported palladium tin tantalum nitride nano electro-catalyst for a direct ethanol and methanol fuel cell is a core-shell type catalyst with palladium tin tantalum nitride as a shell and carbon as a core, and has a molecular formula of PdSn @ TaN/C; the mass percentages of the components of palladium, tin, tantalum nitride and conductive carbon black in the catalyst are respectively 2-10%, 2-15%, 15-70% and 15-70%.
The preparation method of the carbon-supported palladium tin tantalum nitride nano electro-catalyst for the direct ethanol and methanol fuel cell comprises the following steps:
1) adding tantalum nitride, conductive carbon black and ethylene glycol into a container, placing the container on a magnetic stirrer for stirring, and then carrying out ultrasonic treatment to uniformly disperse the tantalum nitride and the conductive carbon black in the ethylene glycol to obtain a mixture A;
2) adding sodium chloropalladate (a palladium precursor and palladium salt), stannous chloride and a potassium hydroxide solution into the mixture A obtained in the step 1), and uniformly stirring the mixture A on a magnetic stirrer to obtain a mixture B, wherein the sodium chloropalladate with the corresponding mass is added according to the mass percent of 2-10% of palladium loading, the stannous chloride with the corresponding mass is added according to the mass percent of 2-15% of tin loading, the potassium hydroxide is added according to 5-30 times of the mass of the sodium chloropalladate, and the reducing agent sodium citrate is added according to 8-10 times of the mass of the sodium chloropalladate;
3) heating the mixture B obtained in the step 2) to 100-130 ℃, stirring for 1-6h, wherein sodium chloropalladate and stannous chloride are respectively reduced into metal palladium and tin to obtain a solid-liquid mixture, and then cooling to room temperature;
4) and washing the solid-liquid mixture cooled to room temperature with deionized water and absolute ethyl alcohol until no ethylene glycol, sodium ions and chloride ions remain, drying in an oven at the temperature of 60-80 ℃ for 6-12 h, and grinding to obtain the carbon-supported palladium tin tantalum nitride nano electro-catalyst for the direct ethyl alcohol and methanol fuel cell.
Preferably, the stirring time on the magnetic stirrer in the step (1) is 15-30 min;
preferably, the time of the ultrasonic treatment in the step (1) is 60-120 min;
preferably, the mass ratio of the tantalum nitride to the conductive carbon black in the step (1) is 2:1, and the amount of the tantalum nitride and the ethylene glycol is related to 1mL of ethylene glycol per 4mg of tantalum nitride. The catalyst acts as an anode electrocatalyst for direct ethanol and methanol fuel cells.
According to the preparation method of the carbon-supported palladium tin tantalum nitride nano electro-catalyst for the direct ethanol and methanol fuel cell, the dosages of the sodium chloropalladate, the stannous chloride, the tantalum nitride and the ethylene glycol can be increased or reduced in an equal ratio. Through structural characterization and analysis of the final product, the palladium tin tantalum nitride is uniformly dispersed on the surface of the carrier conductive carbon black, and the average particle size of the catalyst is about 2.7 nm. The final product is tested by electrochemical analysis, wherein the oxidation peak current intensity of ethanol and methanol is 13025.84 and 3293.46A g respectivelyPd -126.9 times and 15.6 times, respectively, that of commercial palladium on carbon.
According to the invention, the nitride and the oxophilic metal are introduced into the carbon-supported palladium-based catalyst, so that the activity, the anti-poisoning capability and the stability of the catalyst are obviously improved, the use amount of noble metal is effectively reduced, and the preparation cost of the catalyst is reduced. Compared with the prior art, the invention has the following advantages:
1. the invention is a method for preparing the carbon-supported tantalum palladium tin nitride electrocatalyst for the first time, and the preparation method has mild conditions, simple and controllable operation, energy conservation and environmental protection, and is beneficial to realizing industrial production. The tantalum nitride palladium tin nano catalyst loaded on the conductive carbon black and uniformly dispersed is obtained by doping the tantalum nitride and the palladium tin catalyst for the first time, and the tantalum nitride palladium tin nano catalyst shows extremely excellent ethanol and methanol electrocatalytic oxidation performance.
2. According to the invention, the carbon-supported tantalum-palladium-tin nitride electrocatalyst is prepared by using an ethylene glycol solvothermal method, wherein the ethylene glycol solution has high viscosity and can effectively prevent agglomeration, so that palladium metal is more fully mixed with tantalum nitride and is uniformly dispersed on conductive carbon black, and finally active sites are increased; according to the invention, the alkaline glycol solution is used as a reducing agent, and the reducing agent shows mild reducibility within the temperature range of 100-130 ℃, so that the palladium metal is prevented from being agglomerated due to too high reduction speed to generate larger particles.
3. The invention adds transition metal tantalum nitride in palladium tin catalyst for the first time. In consideration of the electronic characteristic of tantalum nitride platinum, the introduction of tantalum nitride enables the core-shell palladium tin tantalum nitride to more fully utilize the interaction between palladium tin and tantalum nitride, so that the electronic characteristic of the whole catalyst is changed, the adsorption of an intermediate product is further improved, the catalytic activity and stability are improved, the use amount of palladium is reduced, and the poisoning resistance of the catalyst is also improved.
4. The carbon-supported palladium tin tantalum nitride (PdSn-TaN/C) nano electro-catalyst prepared by the invention is firstly applied to the aspect of direct ethanol and methanol fuel cells. The method has the advantages that the method still has high electro-catalytic activity (26.9 times and 15.6 times of the commercial palladium-carbon catalytic activity), strong CO poisoning resistance, stability and the like under the condition of low noble metal consumption (2.86%) of the electro-oxidation of ethanol and methanol under the alkaline condition, so that the cost is reduced, the efficiency of the fuel cell and the utilization rate of the noble metal are improved, and a new thought is provided for promoting the development of the high-efficiency and low-cost fuel cell catalyst.
Drawings
FIG. 1 is an X-ray diffraction image of the carbon-supported palladium-tin tantalum nitride nano-electrocatalyst prepared in the first example.
FIG. 2 is a palladium peak fit of the X-ray photoelectron spectrum of the carbon-supported tantalum palladium tin nitride nano electrocatalyst prepared in the first example.
FIG. 3 is a high-resolution TEM photograph of the TaPd-Sn/C electrocatalyst prepared in the first example.
FIG. 4 is a cyclic voltammogram of the carbon-supported tantalum-palladium-tin-nitride nanoelectrocatalyst prepared in example one, measured in a nitrogen-saturated mixture of 1M sodium hydroxide and 1M ethanol at a scan rate of 50mV/s at room temperature.
FIG. 5 is a cyclic voltammogram of the carbon-supported tantalum-palladium-tin-nitride nanoelectrocatalyst prepared in example one, measured at room temperature with a scanning speed of 50mV/s in a mixed solution of 1M sodium hydroxide and 1M methanol saturated with nitrogen.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
The first embodiment is as follows:
the embodiment of the invention relates to a preparation method of a carbon-supported palladium tin tantalum nitride nano electrocatalyst for a direct ethanol and methanol fuel cell, which comprises the steps of adding 270mg of tantalum nitride, 135mg of conductive carbon black and 67.5mL of ethylene glycol into a container, placing the container on a magnetic stirrer, stirring for 15min, and carrying out ultrasonic treatment for 120min to ensure that the tantalum nitride and the conductive carbon black are uniformly dispersed in the ethylene glycol to obtain a mixture A.
Adding 4.9mg of sodium chloropalladate, 16.38mg of stannous chloride, 40mg of sodium citrate and 89.8mg of potassium hydroxide into 8mL of the mixture A, placing the mixture on a magnetic stirrer, stirring for 30min, then heating to 120 ℃, stirring for 2h, wherein the sodium chloropalladate and the stannous chloride are respectively reduced into metal palladium and tin to obtain a solid-liquid mixture, and then cooling to room temperature.
And (3) washing the solid-liquid mixture cooled to room temperature with deionized water and absolute ethyl alcohol until no ethylene glycol, sodium ions and chloride ions remain, drying in an oven at 60 ℃ for 12h, and grinding to obtain the palladium-tin-tantalum nitride-on-carbon nano electrocatalyst (the mass percentages of palladium, tin, tantalum nitride and conductive carbon black are 2.86%, 9.56%, 58.38% and 29.20%) for the direct ethanol and methanol fuel cell.
The catalyst prepared in this example was characterized by its structure, and the characteristic peak of tantalum nitride, the characteristic spectrum of X-ray photoelectron (fig. 2) and the characteristic of palladium (fig. 3) can be seen from the X-ray diffraction photograph (fig. 1), wherein the average particle size of the catalyst is 2.7nm, the catalyst is uniformly dispersed, and most of the palladium exists on the surface of the catalyst as palladium in zero valence state. The oxidation peak current intensity in the forward scan (fig. 4, fig. 5, table 1) represents the electrocatalytic oxidation performance, and it can be seen that the electrocatalytic performance of the palladium-tin-tantalum nitride-on-carbon nano electrocatalyst ethanol and methanol is 26.9 times and 15.6 times that of the commercial palladium-carbon, which shows that the synergistic effect of tantalum nitride and tin on the palladium catalyst effectively improves the catalytic performance of ethanol and methanol.
TABLE 1 catalyst Performance for direct ethanol and methanol Fuel cells
Example two:
the embodiment of the invention relates to a preparation method of a palladium-on-carbon tantalum nitride nano electrocatalyst for a direct ethanol and methanol fuel cell, which comprises the steps of adding 270mg of tantalum nitride, 135mg of conductive carbon black and 67.5mL of ethylene glycol into a container, placing the container on a magnetic stirrer, stirring for 30min, and carrying out ultrasonic treatment for 120min to ensure that the tantalum nitride and the conductive carbon black are uniformly dispersed in the ethylene glycol to obtain a mixture A.
Adding 4.9mg of sodium chloropalladate, 3.42mg of stannous chloride, 40mg of sodium citrate and 89.8mg of potassium hydroxide into 8mL of the mixture A, placing the mixture on a magnetic stirrer, stirring for 30min, then heating to 120 ℃, stirring for 2h, wherein the sodium chloropalladate and the stannous chloride are reduced into metal palladium to obtain a solid-liquid mixture, and then cooling to room temperature.
And (3) washing the solid-liquid mixture cooled to room temperature with deionized water and absolute ethyl alcohol until no ethylene glycol, ammonium ions and chloride ions remain, drying in an oven at 60 ℃ for 12h, and grinding to obtain the palladium-tin-tantalum nitride-on-carbon nano electro-catalyst (the mass percentages of palladium, tin, tantalum nitride and conductive carbon black are 2.86%, 2%, 63.43% and 31.71%) for the direct ethanol and methanol fuel cell.
The performance of this catalyst was evaluated (see table 1) where the peak oxidation current intensity represents the electrocatalytic oxidation performance, and it can be seen that the ethanol and methanol catalytic performance of the palladium-on-carbon tin tantalum nitride nanoelectrocatalyst is 22.37 and 7.95 times that of the commercial palladium-on-carbon.
Example three:
the embodiment is a preparation method of a carbon-supported palladium tin tantalum nitride nano electrocatalyst for a direct ethanol and methanol fuel cell, which is to add 270mg of tantalum nitride, 135mg of conductive carbon black and 67.5mL of ethylene glycol into a container, place the container on a magnetic stirrer to stir for 20min, and perform ultrasonic treatment for 60min to uniformly disperse the tantalum nitride and the conductive carbon black in the ethylene glycol to obtain a mixture A.
Adding 4.9mg of sodium chloropalladate, 5.46mg of stannous chloride, 40mg of sodium citrate and 89.8mg of potassium hydroxide into 8mL of the mixture A, placing the mixture on a magnetic stirrer, stirring for 30min, then heating to 100 ℃ and stirring for 2h, wherein the sodium chloropalladate and the stannous chloride are respectively reduced into metal palladium and tin to obtain a solid-liquid mixture, and then cooling to room temperature.
And (3) washing the solid-liquid mixture cooled to room temperature with deionized water and absolute ethyl alcohol until no ethylene glycol, sodium ions and chloride ions remain, drying the solid-liquid mixture in an oven at 80 ℃ for 6 hours, and grinding the dried solid-liquid mixture to obtain the palladium-tin-tantalum nitride-on-carbon nano electro-catalyst (the mass percentages of the components of palladium, tin, tantalum nitride and conductive carbon black are 2.86%, 3.18%, 62.64% and 31.32%) for the direct ethanol and methanol fuel cell.
The performance of the catalyst was evaluated, wherein the peak current intensities of the oxidation of ethanol and methanol were 9188.37 and 2256.84Ag, respectivelyPd -1。
Example four:
the embodiment of the invention relates to a preparation method of a carbon-supported palladium tin tantalum nitride nano electrocatalyst for a direct ethanol and methanol fuel cell, which comprises the steps of adding 270mg of tantalum nitride, 135mg of conductive carbon black and 67.5mL of ethylene glycol into a container, placing the container on a magnetic stirrer, stirring for 15min, and carrying out ultrasonic treatment for 70min to uniformly disperse the tantalum nitride and the conductive carbon black in the ethylene glycol to obtain a mixture A.
Adding 4.9mg of sodium chloropalladate, 21.84mg of stannous chloride, 70mg of sodium citrate and 89.8mg of potassium hydroxide into 8mL of the mixture A, placing the mixture on a magnetic stirrer, stirring for 30min, then heating to 130 ℃, stirring for 2h, wherein the sodium chloropalladate and the stannous chloride are respectively reduced into metal palladium and tin to obtain a solid-liquid mixture, and then cooling to room temperature.
And (3) washing the solid-liquid mixture cooled to room temperature with deionized water and absolute ethyl alcohol until no ethylene glycol, ammonium ions and chloride ions remain, drying in an oven at 60 ℃ for 12h, and grinding to obtain the palladium-tin-tantalum nitride-on-carbon nano electro-catalyst (the mass percentages of the palladium, tin, tantalum nitride and conductive carbon black are 2.86%, 12.75%, 56.26% and 28.13%) for the direct ethanol and methanol fuel cell.
The performance of the catalyst was evaluated, wherein the peak current intensities of the oxidation of ethanol and methanol were 9746.59 and 2748.76Ag, respectivelyPd -1。
Comparative example one:
the comparative example is a preparation method of a carbon-supported palladium tin nano electro-catalyst for a direct ethanol and methanol fuel cell, 135mg of conductive carbon black and 67.5mL of ethylene glycol are added into a container, the container is placed on a magnetic stirrer to be stirred for 20min, and ultrasonic treatment is carried out for 120min, so that the conductive carbon black is uniformly dispersed in the ethylene glycol, and a mixture A is obtained.
1.47mg of sodium chloropalladate, 4.9mg of stannous chloride, 40mg of sodium citrate and 89.8mg of potassium hydroxide are added to 8mL of the above mixture A, placed on a magnetic stirrer and stirred for 30min, and then heated to 120 ℃ and stirred for 2 h. Wherein the sodium chloropalladate and the stannous chloride are respectively reduced into metal palladium and tin to obtain a solid-liquid mixture, and then the solid-liquid mixture is cooled to room temperature.
And (3) washing the solid-liquid mixture cooled to room temperature with deionized water and absolute ethyl alcohol until no ethylene glycol, sodium ions and chloride ions remain, drying in an oven at 60 ℃ for 12h, and grinding to obtain the palladium-tin-on-carbon nano electro-catalyst (the mass percentages of palladium, tin and conductive carbon black are 2.86%, 9.56% and 87.58%) for the direct ethanol and methanol fuel cell.
The performance of this catalyst was evaluated (see table 1) where the oxidation peak current intensity represents the electrocatalytic oxidation performance, and it can be seen that the ethanol and methanol performance of the palladium-tin-on-carbon nanoelectrocatalyst is 10.2 times that of the commercial palladium-carbon.
Comparative example two:
comparative example two is a palladium-on-carbon copper tantalum nitride catalyst described in the issued patent (application or patent No.: 202010440648.6).
Comparative example three:
comparative example three was a commercial palladium on carbon catalyst purchased.
The applicant declares that the above embodiments are only preferred embodiments of the present invention and do not limit the present invention. That is, the present invention is not limited to the scope of the present invention, but the detailed method of the present invention is illustrated by the examples. It should be clear to those skilled in the art that any modifications to the present invention, equivalent substitutions of the raw materials of the product of the present invention, additions of auxiliary components, selection of specific modes, etc., are intended to be included within the scope and disclosure of the present invention.