Disclosure of Invention
It is an object of the present invention to overcome at least one of the disadvantages of the prior art and to provide a Pt alloy with a higher HOR catalytic activity and its use.
The technical scheme adopted by the invention is as follows:
in a first aspect of the present invention, there is provided:
a Pt alloy having a specific surface area of not less than 30m2The grain diameter is 3-9 nm, and the Pt alloy is selected from the following components:
the Pt-Ir alloy comprises 45 to 55 percent of Ir in molar percentage and the balance of Pt; or
The alloy comprises Pt-Au, wherein the mole percentage of Au is 5-15%, and the balance is Pt; or
The Pt-Ag alloy comprises 5-15% of Ag in mole percentage and the balance of Pt.
In some examples, the molar percentage of Ir in the Pt-Ir alloy is 48 to 55%, preferably 50 to 55%, and more preferably 52 to 55%.
In some examples, the mole percentage of Au in the Pt-Au alloy is 9-13%, preferably 11-13%.
In some examples, the molar percentage of Ag in the Pt-Ag alloy is 8-15%, preferably 8-12%, and more preferably 10-12%.
In some examples, the mole percentage of Ir in the Pt-Ir alloy is 52%.
In some examples, the mole percentage of Au in the Pt-Au alloy is 11%.
In some examples, the mole percent of Ag in the Pt-Ag alloy is 10%.
In a second aspect of the present invention, there is provided:
use of a Pt alloy as described in the first aspect of the invention in the manufacture of a catalyst for the anode of a fuel cell MEA.
In some examples, the Pt alloy is loaded at the anode of the MEA at a load of 0.01-0.05 mg/cm2,0.01~0.04mg/cm2,0.01~0.03mg/cm2。
In a third aspect of the present invention, there is provided:
an MEA comprising an anode carrying the Pt alloy of the first aspect of the present invention.
In some examples, the Pt alloy is loaded at the anode of the MEA at a load of 0.01-0.05 mg/cm2,0.01~0.04mg/cm2,0.01~0.03mg/cm2。
In a fourth aspect of the present invention, there is provided:
a proton exchange membrane fuel cell having an anode employing a catalyst comprising a Pt alloy according to the first aspect of the present invention; or with an MEA according to the third aspect of the invention.
In a fifth aspect of the present invention, there is provided:
the method for producing a Pt alloy according to the first aspect of the present invention includes:
s1) dissolving a water-soluble Pt salt and another water-soluble alloy element salt in a polar solvent;
s2), adding a reducing agent, and reacting to obtain the Pt alloy.
In some examples, the Pt alloy is a Pt-Ir alloy, and the method of making comprises:
s1) dissolving a Pt salt and an Ir salt in 1, 2-propylene glycol, and fully carrying out solvothermal reaction at 130-180 ℃ in a pressure container;
s2) after the solvothermal reaction is finished, cooling, adding a non-polar solution of octane thiol, and fully mixing;
s3), adding water, mixing uniformly, separating liquid, collecting a non-polar solvent phase, and removing the non-polar solvent to obtain the Pt-Ir alloy.
In some examples, the Pt alloy is a Pt-Au alloy, and the method of making comprises:
s1) dripping the Pt salt solution and the Au salt solution into the citric acid solution, and fully and uniformly mixing;
s2) adding NaBH4Fully and uniformly mixing the solution;
s3), adding 2-propanol, and fully and uniformly mixing for reaction;
s4), collecting a solid phase product after the reaction is finished, washing and drying to obtain the Pt-Au alloy.
In some examples, the Pt alloy is a Pt-Ag alloy, and the method of making comprises:
s1) mixing the Pt salt solution, the Ag salt solution, the poly (N-isopropyl acrylamide) water solution and water evenly;
s2), adding a formaldehyde solution, uniformly dispersing, transferring into a hydrothermal reaction kettle, and reacting at 120-160 ℃;
s3), collecting a solid-phase product after the reaction is finished, washing and drying to obtain the Pt-Ag alloy.
In some examples, the Pt salt is selected from H2PtCl6The Ir salt is selected from IrCl3The Au salt is selected from HAuCl4The Ag salt is AgNO3。
In some examples, the method of making the Pt-Ir alloy includes:
S1)0.27mmol IrCl3and 0.25mmol of PtCl2Dissolving in 100mL of 1, 2-propylene glycol, reacting at 165 ℃ for 15min, and vigorously stirring until the solution becomes dark brown to obtain a colloidal solution;
s2) cooling the colloidal solution to room temperature, adding a mixed solution of 20mL of toluene and 0.3g of octane thiol, and stirring overnight;
s3) adding 20mL of deionized water, separating, collecting a toluene phase, and distilling under reduced pressure to obtain the product.
In some examples, the method of making the Pt-Au alloy includes:
s1) dissolving 1.5mL of 0.1 mM sodium citrate solution in 400mL of water, stirring vigorously for 10min, and adding 1mL of 9.1mg Pt/mL H dropwise2PtCl6And 0.25mL4.46 mg Au/mL HAuCl4Stirring the solution vigorously for 10 min;
s2) adding fresh NaBH in one portion4Solution, stirring vigorously for 5min, the NaBH4The solution was composed of 22.5mg NaBH4Dissolved in a solution of 3.5mL of water and 1.5mL of 0.1M sodium citrate;
s3) adding 10mL of 2-propanol, and stirring for 4 h;
s4), centrifugally collecting the product, washing the product by deionized water until no chloride ions exist, and drying the product to obtain the Pt-Au alloy.
In some examples, the method of preparing the Pt-Ag alloy includes:
S1)0.21mL50 mM AgNO3aqueous solution, 1.25mL50 mM H2PtCl6The solution, 5.0mL of 50 mM Mw. ═ 2500 poly (N-isopropylacrylamide) solution, and 35mL were mixed well;
s2), dropwise adding 2.5mL of 40 wt.% formaldehyde solution, performing ultrasonic treatment for 5min, transferring the solution into a 100mL hydrothermal reaction kettle, sealing, and keeping the temperature at 140 ℃ for 6 hours;
s3), cooling to room temperature after the reaction is finished, centrifugally collecting the product, washing for 3 times by deionized water and acetone, and drying to obtain the Pt-Ag alloy.
The invention has the beneficial effects that:
the Pt alloy has better HOR catalytic activity, can reduce the consumption of PGM under the condition of ensuring that the performance of the anode is not influenced when being applied to the MEA anode of the PEMFC, and is beneficial to reducing the cost of the PEMFC.
Detailed Description
A representative Pt alloy was prepared as follows:
the preparation method of the Pt-Ir alloy comprises the following steps:
S1)0.27mmol IrCl3and 0.25mmol of PtCl2Dissolving in 100mL of 1, 2-propylene glycol, reacting at 165 ℃ for 15min, and vigorously stirring until the solution becomes dark brown to obtain a colloidal solution;
s2) cooling the colloidal solution to room temperature, adding a mixed solution of 20mL of toluene and 0.3g of octane thiol, and stirring overnight;
s3) adding 20mL of deionized water, separating, collecting a toluene phase, and distilling under reduced pressure to obtain the product.
The preparation method of the Pt-Au alloy comprises the following steps:
s1) dissolving 1.5mL of 0.1 mM sodium citrate solution in 400mL of water, stirring vigorously for 10min, and adding 1mL of 9.1mg Pt/mL H dropwise2PtCl6And 0.25mL4.46 mg Au/mL HAuCl4Stirring the solution vigorously for 10 min;
s2) adding fresh NaBH in one portion4Solution, stirring vigorously for 5min, the NaBH4The solution was composed of 22.5mg NaBH4Dissolved in a solution of 3.5mL of water and 1.5mL of 0.1M sodium citrate;
s3) adding 10mL of 2-propanol, and stirring for 4 h;
s4), centrifugally collecting the product, washing the product by deionized water until no chloride ions exist, and drying the product to obtain the Pt-Au alloy.
The preparation method of the Pt-Ag alloy comprises the following steps:
S1)0.21mL50 mM AgNO3aqueous solution, 1.25mL50 mM H2PtCl6The solution, 5.0mL of 50 mM Mw. ═ 2500 poly (N-isopropylacrylamide) solution, and 35mL were mixed well;
s2), dropwise adding 2.5mL of 40 wt.% formaldehyde solution, performing ultrasonic treatment for 5min, transferring the solution into a 100mL hydrothermal reaction kettle, sealing, and keeping the temperature at 140 ℃ for 6 hours;
s3), cooling to room temperature after the reaction is finished, centrifugally collecting the product, washing for 3 times by deionized water and acetone, and drying to obtain the Pt-Ag alloy.
S4) by adjusting the proportion of the water-soluble metal salt, Pt alloys with different proportions can be obtained.
The detection result shows that the specific surface area of the Pt alloy particles obtained by the solution reaction is not less than 30m2(iii) per gram, the particle size is between 3 and 9 nm.
Other methods can also be used for reference to prepare the Pt alloy.
HOR catalytic Activity comparison of different Pt alloys
Taking the prepared specific surface area not less than 30m2(g) Pt alloy particles with different molar compositions and particle diameters of 3-9 nm (the specific surface area, the particle diameters and the like have no obvious difference compared), and the loading capacity (0.005-0.070 mg/cm) of the Pt alloy particles at different anodes is respectively tested2) Anode over-potentials (performance losses) were calculated and the HOR catalytic activity was calculated under different conditions, and the results are shown in table 1.
TABLE 1 Effect of different treatments on anodic overpotential (HOR activity)
As is clear from table 1, there is a narrower range of alloy compositions for the PtIr, PtAu and PtAg alloys, within which Pt alloys unexpectedly have better HOR catalytic activity (manifested as a significant drop in anode overpotential) than Pt, thereby improving the performance of the MEA as a whole.
0.025mg/cm respectively loaded on the anode2Pt or Pt alloy (Pt)52Ir48) MEAs were fabricated and tested for polarization curves under different conditions, with the results shown in figure 2. The results show that the cell voltage increased by about 25mV for the Pt alloy at 75 ℃, 136kPa, 100% RH compared to the conventional anode HOR catalyst Pt/C due to the increase in HOR catalytic activity (resulting in a decrease in anode overpotential).