CN-121983599-A - Carbon nano tube loaded ternary PtCoNi composite catalyst and preparation method and application thereof

CN121983599ACN 121983599 ACN121983599 ACN 121983599ACN-121983599-A

Abstract

The application discloses a carbon nano tube supported ternary PtCoNi composite catalyst, a preparation method and application thereof, belonging to the field of electrochemistry, wherein a carbon nano tube is dissolved in nitric acid solution and stirred for 5 hours at 80 ℃ and 800r/min; washing the solution with deionized water until the filtrate is neutral, drying at 60 ℃ for 8 hours to obtain a pretreated carbon nanotube, dissolving the pretreated carbon nanotube in deionized water in a centrifuge tube, ultrasonically obtaining a solution A in the centrifuge tube, ultrasonically obtaining a solution B in the centrifuge tube, pouring the solution B in the solution A to form a solution C, ultrasonically transferring the solution C to a flask after ultrasonic treatment of 10 min and magnetically stirring at the rotating speed of 800r/min, dissolving ascorbic acid in the centrifuge tube, adding the solution C after ultrasonic treatment until the ascorbic acid is dissolved, heating to 90 ℃, continuously stirring for 12 hours, and vacuum drying at 60 ℃ for 8 hours to obtain the carbon nanotube.

Inventors

GE MING
YUAN XIAOLEI
XIAO KAIWEN
DING JINJIN
LIU JUNJIE

Assignees

南通大学

Dates

Publication Date: 20260505
Application Date: 20251224

Claims (10)

1. The preparation method of the carbon nano tube supported ternary PtCoNi composite catalyst is characterized by comprising the following specific steps: Preparing a nitric acid solution with the volume concentration of 20 percent, taking 20-40mg of carbon nano tubes, adding the 20 percent nitric acid solution into a 50mL flask, placing the flask into the flask, controlling the rotating speed to be 700-900r/min under the condition of 70-90 ℃, stirring for 4-6h, washing the solution with deionized water until filtrate is neutral after stirring is finished, and then drying the solution for 7-9h under the temperature of 50-70 ℃ to obtain pretreated carbon nano tubes; Secondly, 1-3mg of pretreated carbon nanotubes are placed in a centrifuge tube, 4-6 mL deionized water is added, and the solution A is obtained by ultrasonic treatment in the centrifuge tube for 10-40 min; thirdly, taking metal precursors of potassium chloroplatinite, cobalt nitrate hexahydrate ‌ and nickel nitrate hexahydrate, adding 5mL of deionized water, and then performing ultrasonic treatment in a centrifuge tube for 10-600s to obtain a solution B; Pouring the solution B into the solution A, performing ultrasonic treatment for 5-30min to form a solution C, transferring the solution C into a 50mL flask, performing magnetic stirring, controlling the magnetic stirring rotation speed to be 700-900 r/min, stirring for 10-30min, dissolving 30-50mg of ascorbic acid into 5-15mL of deionized water, placing into a centrifuge tube, performing ultrasonic treatment for 11-19s until the ascorbic acid is completely dissolved to obtain an ascorbic acid solution, adding the ascorbic acid solution while stirring in the magnetic stirring of the solution C, and performing magnetic stirring for 50-70min at the rotation speed of 700-900 r/min to form a solution D; and fifthly, heating the solution D to 80-100 ℃, maintaining the rotating speed of 700-900 r/min, continuing to magnetically stir for 11-13h, washing with absolute ethyl alcohol twice after stirring, and finally drying in vacuum for 7-9h at 50-70 ℃ to obtain the target material carbon nano tube supported ternary PtCoNi composite catalyst.
2. The method for preparing the carbon nanotube-supported ternary PtCoNi composite catalyst according to claim 1, wherein in the first step, 10mL of concentrated nitric acid is dissolved in 24mL of deionized water to prepare a nitric acid solution with a volume concentration of 20%.
3. The method for preparing the carbon nanotube-supported ternary PtCoNi composite catalyst according to claim 2, wherein in the first step, 30mg of carbon nanotubes are taken, 20% nitric acid solution is added, the rotation speed is controlled to be 800r/min under the condition of 80 ℃, stirring is carried out for 5 hours, after stirring is finished, deionized water is used for washing the solution until filtrate is neutral, and then drying is carried out for 8 hours under the condition of 60 ℃, so that the pretreated carbon nanotubes are prepared.
4. The method for preparing the carbon nanotube-supported ternary PtCoNi composite catalyst according to claim 1, wherein in the second step, 2mg of pretreated carbon nanotubes are placed in a centrifuge tube, 5 mL deionized water is added, and the centrifuge tube is subjected to ultrasonic treatment for 30min, so that the pretreated carbon nanotubes are uniformly dispersed in the deionized water, and a solution A is obtained.
5. The method for preparing the carbon nanotube-supported ternary PtCoNi composite catalyst according to claim 1, wherein in the third step, the molar ratio of potassium chloroplatinite, cobalt nitrate hexahydrate ‌ and nickel nitrate hexahydrate is potassium chloroplatinite, cobalt nitrate hexahydrate, nickel nitrate hexahydrate=2:1:3, 2:0:4 and 2:2:2, respectively.
6. The method for preparing the carbon nanotube-supported ternary PtCoNi composite catalyst according to claim 1, wherein in the fourth step, solution B is poured into solution A, ultrasonic treatment is carried out for 10min to form solution C, the solution C is transferred into a 50mL flask for magnetic stirring, the magnetic stirring speed is controlled to be 800 r/min, stirring is carried out for 20min, 40mg of ascorbic acid is dissolved in 10mL of deionized water and placed in a centrifuge tube, ultrasonic treatment is carried out for 10-600s until the ascorbic acid solution is completely dissolved, the ascorbic acid solution is added while stirring in the magnetic stirring of the solution C, and the magnetic stirring is carried out for 1h while maintaining the rotational speed of 800 r/min to form solution D.
7. The preparation method of the carbon nanotube-supported ternary PtCoNi composite catalyst according to claim 1, which is characterized by comprising the steps of heating a solution D to 90 ℃, maintaining the rotation speed of 800 r/min, continuing to magnetically stir for 12h, washing with absolute ethyl alcohol twice after stirring, washing with absolute ethyl alcohol at the rotation speed of 7500-8500 r/min, centrifuging for 4-6min each time, and finally vacuum drying at 60 ℃ for 8h to obtain the target material carbon nanotube-supported ternary PtCoNi composite catalyst for subsequent electrochemical testing.
8. The method for preparing the carbon nanotube-supported ternary PtCoNi composite catalyst according to claim 7, wherein the absolute ethyl alcohol is washed twice, and the rotation speed is controlled to be 8000 r/min and the absolute ethyl alcohol is centrifuged for 5min each time.
9. A carbon nanotube-supported ternary PtCoNi composite catalyst prepared by the method of any one of claims 1 to 8.
10. Use of the carbon nanotube-supported ternary PtCoNi composite catalyst prepared by the preparation method of any one of claims 1 to 8 in the preparation of an ammonia fuel cell.

Description

Carbon nano tube loaded ternary PtCoNi composite catalyst and preparation method and application thereof Technical Field The invention belongs to the technical field of electrochemistry, and particularly relates to a carbon nano tube loaded ternary PtCoNi composite catalyst and a preparation method and application thereof. Background In the electrochemical field, an Ammonia Oxidation Reaction (AOR) is a core electrode reaction for supporting efficient operation of new energy devices such as an ammonia fuel cell, and the kinetic rate and the reaction selectivity directly determine the energy conversion efficiency and the long-term stability of the device, so that development of a catalytic material with high activity, high stability and low cost becomes a research core direction in the field. The traditional AOR catalytic material is mainly a platinum (Pt) base noble metal catalyst, pt can effectively reduce the reaction activation energy by virtue of excellent electron conductivity and surface adsorption capacity, but Pt resources are scarce and expensive, and agglomeration, dissolution or poisoning easily occur in long-term electrochemical circulation, so that the catalytic activity is rapidly attenuated, and the large-scale commercial application of the catalytic material is severely limited. In order to solve the problem, the technical personnel in the art can utilize the electronic effect (adjusting d-band center of Pt) and geometric effect (optimizing active site spacing) of alloy elements by constructing a Pt-based alloy catalyst (such as PtCo and PtNi alloy) to improve the catalytic activity and reduce the dosage of Pt at the same time, however, nano-scale Pt-based alloy particles still have the problems of poor dispersibility and easy agglomeration, so that the active sites are not exposed enough, and the catalytic performance is difficult to fully develop. The carbon material has high specific surface area, excellent conductivity and chemical stability, and becomes an ideal carrier for loading the metal nanoparticle catalyst. The Carbon Nanotubes (CNTs) can provide a stable load substrate for metal nano particles by virtue of a unique one-dimensional tubular structure, inhibit particle aggregation, and construct a rapid electron transmission channel and a substance diffusion path so as to further strengthen catalytic reaction kinetics. Based on the method, pt-based alloy nano particles are combined with CNTs, and a carbon nano tube supported Pt-based alloy composite catalyst is constructed, so that the method becomes a key technical path for combining catalytic activity, stability and cost control. At present, the preparation of the composite catalyst still faces challenges that the existing synthesis method (such as a dipping reduction method and a hydrothermal method) is easy to cause uneven alloy particle size and poor dispersibility, the component proportion and the crystal structure of the Pt-based alloy are difficult to accurately regulate and control, and the repeatability and the stability of the catalytic performance are further affected, and meanwhile, the suitability research of the catalyst in an AOR action mechanism, an active site structure-activity relationship and an actual battery device still needs to be further deepened, so that the preparation method with simple process and strong controllability is developed, the electrochemical performance of the catalyst is systematically explored, and the preparation method has important significance in promoting the industrialized development of new energy devices. Disclosure of Invention The invention provides a carbon nano tube supported ternary PtCoNi composite catalyst and a preparation method and application thereof, aiming at solving the core technical problems of poor catalyst dispersibility, contradiction between the dosage cost and catalytic activity of noble metal Pt, inactivation in the electrocatalytic process of the catalyst, interference of impurities on catalytic performance and the like in the prior art, enhancing the adsorption capacity of a carbon nano tube carrier and PtCoNi metal precursor by acidizing CNTs through concentrated nitric acid and containing oxygen functional groups, effectively avoiding agglomeration of metal particles by combining an ultrasonic dispersion step, realizing uniform dispersion of alloy nano particles on the surface of the carrier, adopting Pt, co and Ni transition metals to form ternary alloy, greatly reducing the dosage of noble metal Pt while guaranteeing the catalytic activity, and solving the problems of high cost and difficult large-scale application of pure Pt catalysts. The application aims to provide a carbon nano tube supported ternary PtCoNi composite catalyst FeC-G@M-C & P, a preparation method and application thereof, wherein metal particles and CNTs form a more stable combined structure through two-step treatment of 'ascorbic acid reduction' and 'heating to 90 ℃ for crystallizatio