CN-121992447-A - Preparation method of palladium quantum dot loaded barium titanate composite material

Abstract

The application discloses a preparation method of a palladium quantum dot loaded barium titanate composite material, which improves piezoelectric catalysis performance through morphology regulation and interfacial engineering. By adopting the electrostatic spinning technology and matching with the 700 ℃ accurate annealing strategy, the BTO nanowire is converted from a cubic phase to a ferroelectric tetragonal phase, so that the built-in electric field and piezoelectric response are enhanced, the brittle fracture of the nanowire caused by high temperature is avoided, and the integrity and flexibility of a one-dimensional structure are ensured. And in the active site loading stage, an ultrasonic dispersion and intense stirring synchronous process in an ice bath environment is adopted, local concentration polarization is eliminated, nanowire aggregation is disassembled, and Pd (111)/BTO (110) epitaxial matching heterojunction is uniformly formed on a BTO (110) crystal face in situ by driving the palladium quantum dot. The high-quality Schottky interface strengthens charge transfer efficiency, improves catalytic reduction kinetics, and improves 2.8 times compared with pure BTO, wherein the hydrogen evolution rate reaches 3464.28 mu mol seed h-1 under the load of 0.75wt.% palladium. The technological parameters are easy to control, the cost is low, and a feasible technical scheme is provided for the piezoelectric catalytic hydrogen production industrialization.

Inventors

• HUANG WEICHENG
• XU WEIRANG
• YUE WENYING
• XU WANGYING
• Lin Qiubao

Assignees

• 集美大学

Dates

Publication Date

20260508

Application Date

20260209

Claims (8)

1. 1. The preparation method of the palladium quantum dot loaded barium titanate composite material is characterized by comprising the following steps of: (1) Dispersing calcined barium titanate nanowires in a mixed solvent composed of deionized water and ethylene glycol to obtain a dispersion liquid; (2) Placing the dispersion liquid in the step (1) in an ice bath environment, and simultaneously carrying out ultrasonic dispersion and vigorous stirring to obtain a suspension liquid; (3) Adding sodium tetrachloropalladate into the suspension in the step (2), and continuously stirring to ensure that palladium ions are uniformly adsorbed on the surface of the barium titanate nanowire to obtain a composite dispersion; (4) Adding sodium hydroxide solution into the composite dispersion liquid in the step (3) to obtain an alkaline system; (5) Under the conditions of ice bath and vigorous stirring, dropwise adding sodium borohydride solution into an alkaline system, maintaining the ice bath environment to complete the reduction reaction, and ensuring that palladium quantum dots uniformly grow on the barium titanate surface in situ to obtain a reaction product; (6) The reaction product is dried after repeated washing with deionized water and ethanol for a plurality of times.
2. 2. The method for preparing the palladium quantum dot loaded barium titanate composite material according to claim 1, wherein the weight ratio of deionized water to ethylene glycol in the step (1) is 25:1.
3. 3. The method for preparing the palladium quantum dot loaded barium titanate composite material according to claim 1, wherein the ice bath temperature in the step (2) is 0-4 ℃, and the time of ultrasonic dispersion and stirring is 1h.
4. 4. The method for preparing the palladium quantum dot loaded barium titanate composite material according to claim 1, wherein the stirring time in the step (3) is 0.5h.
5. 5. The method for preparing the palladium quantum dot supported barium titanate composite material according to claim 1, wherein the pH of the alkaline system in the step (4) is adjusted to 10.
6. 6. The method for preparing the palladium quantum dot supported barium titanate composite material according to claim 1, wherein the drying temperature in the step (5) is 70 ℃.
7. 7. The method for preparing the palladium quantum dot supported barium titanate composite material according to claim 1, wherein the method for preparing the barium titanate nanowire is as follows: Mixing 4-5 parts of ethanol, 1 part of deionized water and 3-4 parts of acetic acid according to parts by weight, adding 5wt.% of polyvinylpyrrolidone, and stirring to obtain a base solution; After the basic solution is stirred to be transparent, adding barium acetate, continuously stirring, then dropwise adding tetrabutyl titanate, setting the molar ratio of the barium to the titanium to be 1:1 according to the stoichiometric ratio, and continuously stirring the final mixed solution for 2 hours to prepare stable precursor sol; Carrying out electrostatic spinning on the prepared precursor sol, wherein the spinning process parameters are that the feeding rate is 3mL/h, and the applied electric field strength is 1.5kV/cm; The two-step annealing treatment, namely placing the sample collected by electrostatic spinning in an air atmosphere, and adopting a specific two-step heating program for annealing, wherein the first step is to heat to 350 ℃ to finish the removal of the polymer, and the second step is to heat to 550-850 ℃ again to perform crystallization treatment to obtain the sample; and calcining and preserving the temperature of the sample at a target crystallization temperature, and then naturally cooling to obtain the barium titanate nanowire.
8. 8. The method for preparing the palladium quantum dot supported barium titanate composite material according to claim 7, wherein the heating rate in the first heating step is 5 ℃ per minute, and the heating rate in the second heating step is 2 ℃ per minute.

Description

Preparation method of palladium quantum dot loaded barium titanate composite material Technical Field The application belongs to the technical field of piezoelectric catalysis, and particularly relates to a preparation method of a barium titanate composite material. Background The global energy crisis is continuously upgraded, environmental challenges are becoming urgent, and development of clean renewable energy alternatives is urgently needed. The hydrogen energy is an energy carrier with great application prospect in the future by virtue of the outstanding advantages of high energy density and zero carbon emission, so that the research and development of the high-efficiency and low-cost hydrogen production technology is particularly critical. The traditional hydrogen preparation method is mostly dependent on fossil fuel reforming or high-energy-consumption water electrolysis technology, and has the defects of high carbon emission, high energy consumption and the like in the hydrogen production process, so that the clean and sustainable energy development requirements are difficult to meet. In recent years, piezoelectric catalysis technology becomes an innovative sustainable hydrogen production means, and the technology utilizes mechanical energy such as ultrasonic waves, fluid flow vibration and the like to drive chemical reactions such as water decomposition and the like, thereby providing a new technical path for hydrogen energy preparation. The piezoelectric material with the non-centrosymmetric crystal structure generates a spontaneous built-in electric field when being deformed by mechanical force, and the built-in electric field can effectively separate carriers, so that electrons migrate to the surface of the catalyst to participate in hydrogen ion reduction, and holes participate in oxidation reactions such as organic degradation, and the like, thereby realizing efficient implementation of catalytic reaction. Barium titanate (BaTiO 3, BTO for short) is a lead-free ferroelectric material, and is an important research material in the field of piezoelectric catalysis because of excellent piezoelectric response, good chemical stability and environmental friendliness. However, when pure-phase BTO is used as a piezoelectric catalyst, the pure-phase BTO has obvious limitation, and electron-hole pairs generated by the pure-phase BTO are easy to rapidly combine before participating in surface catalytic reaction, so that the quantum efficiency of the material is low, and the catalytic performance is difficult to meet the practical application requirements. In order to improve the catalytic performance of the piezoelectric catalyst, various modification means are formed in the prior art, namely, the piezoelectric catalyst with low-dimensional nano structures such as nanowires, nanoplates and the like is developed, the one-dimensional or two-dimensional low-dimensional structures not only can provide larger specific surface area for catalytic reaction, but also can enable the piezoelectric catalyst to generate larger elastic deformation under ultrasonic vibration, further, the surface reaction process is enhanced, the induced material generates a strong polarization effect, and the catalytic performance is improved, and the built-in electric field formed at the heterojunction can serve as an efficient electron capture center to effectively promote the separation of charges and the migration to a catalytic active site, so that the piezoelectric catalytic activity is improved. However, the hydrogen evolution rate of the BTO-based piezoelectric composite material reported at present still has a great gap from the requirements of practical application, and large-scale application is difficult to realize. Noble metals such as silver (Au), platinum (Pt), palladium (Pd) and the like can effectively accelerate the hydrogen evolution reaction rate determining step because the adsorption energy of hydrogen and the Gibbs free energy of the Hydrogen Evolution Reaction (HER) are close to the optimal values, so the noble metals are widely used as ideal cocatalysts for electrocatalytic water decomposition, but the high cost of raw materials of the noble metal cocatalysts further limits the commercialization popularization and practical application of the noble metal cocatalysts. In summary, various modification means for BTO-based piezocatalysts in the prior art can improve the piezocatalysis performance of materials to a certain extent, but the problems of low hydrogen evolution rate, high use cost of noble metal cocatalysts and the like generally exist, and the dual aims of high piezocatalysis performance and low preparation cost are difficult to realize. Therefore, developing a BTO-based piezocatalyst with both high-pressure catalytic hydrogen evolution performance and low noble metal loading becomes a technical problem to be solved in the art. Disclosure of Invention Based on the above, the research provides a preparat