CN-121972237-A - Non-noble metal doped LaCoO3Base system, preparation method and application

Abstract

The invention belongs to the technical field of photocatalytic hydrogen production, and discloses a non-noble metal doped LaCoO 3 base system, a preparation method and application. Firstly, a sol-gel method is adopted to realize uniform mixing and complexing of metal precursor ions at a molecular level, then under a specific stepped program temperature-controlled air calcination condition, the heterovalent substitution effect of non-noble metal copper ions (Cu 2+ 、Cr 3+ or Ni 2+ is used for replacing Co 3+ ), a large number of uniformly distributed oxygen vacancy defects are forcedly and in situ induced in perovskite (LaCoO 3 ) crystal lattice, and finally, a pure-phase Cu/Cr/Ni doped LaCoO 3 -based solid solution photo-thermal catalyst is obtained and is used for efficient photo-thermal methanol cracking hydrogen production reaction.

Inventors

• SHI WEIDONG
• LU XINYU
• HUANG YUANYONG
• XIE ZHONGKAI

Assignees

• 江苏科技大学

Dates

Publication Date

20260505

Application Date

20260408

Claims (9)

1. 1. The preparation method of the non-noble metal doped LaCoO 3 -based system is characterized by comprising the following steps of: (1) Weighing lanthanum salt, cobalt salt and non-noble metal salt according to a proportion, dissolving the lanthanum salt, cobalt salt and non-noble metal salt in deionized water to obtain a clear mixed metal salt solution, sequentially adding a complexing agent and a crosslinking agent into the solution, dropwise adding a pH regulator, and continuously stirring to obtain a uniform precursor solution; (2) Placing the precursor solution obtained in the step (1) into constant temperature heating equipment for continuous heating and slow stirring, and finally forming viscous wet gel; (3) Transferring the wet gel obtained in the step (2) together with a reaction container into a drying device for continuous drying, dehydrating and expanding the wet gel to form a low-density fluffy spongy xerogel precursor, and then scraping and grinding the spongy xerogel precursor into fine powder; (4) And (3) loading the xerogel fine powder obtained in the step (3) into a crucible with a cover, placing the crucible into a muffle furnace for stepped temperature programming calcination, and naturally cooling the crucible to room temperature along with the furnace after the reaction is finished, thus obtaining the non-noble metal doped LaCoO 3 -based photo-thermal catalyst with rich oxygen vacancies, namely LaCo 0.9 M 0.1 O 3 , wherein M is Cu, cr or Ni.
2. 2. The method of claim 1, wherein in step (1), the lanthanum salt, cobalt salt, non-noble metal salt, complexing agent and crosslinking agent are used in a ratio of 10 mmol:9 mmol:1 mmol:6.304 g:1.8~2.2 mL.
3. 3. The method of claim 1, wherein in step (1), the lanthanum salt is La (NO 3 ) 3 ·6H 2 O, the cobalt salt is Co (NO 3 ) 2 ·6H 2 O, and the non-noble metal salt is anhydrous Cu (NO 3 ) 2 、Cr(NO 3 ) 3 ·9H 2 O or Ni (NO 3 ) 2 ·6H 2 O).
4. 4. The method of claim 1, wherein in step (1), the complexing agent is citric acid monohydrate and the crosslinking agent is ethylene glycol.
5. 5. The method of claim 1, wherein in the step (1), the pH adjuster is ammonia water, and the pH of the solution is accurately adjusted to 6.0-7.0.
6. 6. The preparation method of claim 1, wherein in the step (2), the constant temperature heating device is a water bath or a heat collection type constant temperature magnetic stirrer, and the heating temperature is set to 80-90 ℃.
7. 7. The method of claim 1, wherein in step (3), the drying apparatus is a forced air drying oven, the drying temperature is 120 ℃, and the continuous drying time is 12 h.
8. 8. The method according to claim 1, wherein the step-wise temperature-programmed calcination in the step (4) comprises two continuous stages, namely, the first stage is performed at a temperature ranging from room temperature to 300 ℃, the temperature ranging from 2 ℃ to 3 ℃ per minute, and the temperature is kept at 2h, the second stage is performed at a temperature ranging from 300 ℃ to 700 ℃, the temperature ranging rate is strictly controlled at 2 ℃ per minute, and the temperature is kept at 4 to 6 hours, and the crucible cover is kept in a half-mask state during the whole calcination process.
9. 9. The use of the non-noble metal doped LaCoO 3 matrix prepared by the preparation method according to any one of claims 1-8 for efficiently driving a photo-thermal methanol cracking hydrogen production reaction.

Description

Non-noble metal doped LaCoO 3 base system and preparation method and application thereof Technical Field The invention belongs to the technical field of photocatalytic hydrogen production, and particularly relates to a non-noble metal doped LaCoO 3 matrix system, a preparation method and application thereof. Background In recent years, in a large background that the problem of Energy exhaustion is becoming more and more intense and the problem of environment is becoming more and more severe, the use of photocatalysis or photo-thermal catalysis technology to produce hydrogen as green fuel with zero carbon emission is considered as the basis for future renewable Energy technology applications (d.m. Zhao, et al, nat. Energy 2021, 6, 388-397). However, safe storage and long distance transport of hydrogen has been a bottleneck limiting the large-scale use of hydrogen. Methanol is used as a stable liquid-phase hydrogen storage medium at normal temperature and normal pressure, has extremely high hydrogen-carbon ratio and convenient storage and transportation, and is considered as an ideal liquid hydrogen carrier. Thus, in situ production of hydrogen by steam reforming of methanol is the basis and focus of current energy conversion technologies (m.zhang, d. Liu, et al, catalysts 2025, 15, 36). In practical applications, conventional steam reforming of methanol is a strongly endothermic reaction, which usually needs to be performed at a relatively high temperature, not only consuming a large amount of heat energy, but also easily leading to rapid deactivation of the catalyst. The solar-driven photo-thermal catalysis technology provides a green and efficient way for reducing the reforming reaction temperature. However, from the solar spectrum composition, how to maximize the utilization of full spectrum solar energy and obtain high hydrogen production efficiency at lower temperatures remains a significant challenge for near infrared regions up to 50% (z.c. Lian, et al, j. Am. chem. Soc.2019, 141, 2446-2450). In recent years, scholars at home and abroad develop a series of researches aiming at Gao Shangguang thermal catalytic materials and near infrared light response systems so as to break through the bottleneck of full spectrum absorption. Currently, the design concept and active components of MSR catalysts are mainly focused on two major classes of noble metals (Pt, ru, etc.) and non-noble metal copper-based (x.liu, l. Wang, et al, acta Phys—chim, sin, 2025, 41, 100049). Noble metal monoatomic catalysts (such as single-site Pt 1/CeO2) have excellent low-temperature catalytic activity and C-H/O-H bond activation capability (Z.Qi, L.Chen, et al, J. Am. chem. Soc.2021, 143, 60-64), and photo-thermal methanol hydrogen production mechanisms based on the Pt/TiO 2 system have also been widely studied. Meanwhile, the supported noble metal monoatomic (NM-SA) cocatalyst (such as Pt or Pd monoatomic) can effectively promote the photocatalysts to separate the photocatalysts, thereby improving the hydrogen production performance (J.M. Wang, et al, adv. Energy Mater 2021, 11, 2003575) in multiple. However, the high price of noble metals severely limits their large-scale commercial application. In contrast, non-noble metal Cu-based systems, which are inexpensive and have a naturally high selectivity for MSR reactions, are currently the mainstream. In 2021, zhang Tierui taught that the subject group utilized plasmonic Cu nanoparticles (L-Cu) derived from layered double hydroxides, realized optically driven methanol reforming hydrogen production, and exhibited good potential in terms of photothermal conversion (z. Li, j. Liu, et al, adv. Funct. Mate. 2021). The professor group of the university of western traffic Wei Jin proposes a full-spectrum synergistic photo-thermal catalytic technology, constructs a Pt-CuO x/Cu2 O/CuO heterojunction photo-thermal catalyst, remarkably reduces the energy barrier of the water-gas shift process (D. Li, J. Sun, et al, journal of ENERGY CHEMISTRY2022, 71, 467-474), and develops an efficient solar driven double-bed photo-thermal catalytic reactor (DBPTR) (D. Li, J. Sun, et al, fuel 2023, 349, 129895). While the above work has greatly driven the development of this field, conventional Cu-based catalysts (such as cu—al spinel systems) are highly susceptible to sintering and agglomeration of surface copper particles under high temperature photothermal cycling conditions, resulting in rapid deactivation and poor stability of the catalyst (x.hou, y. Liu, et Al, angel, chem. Int. Ed. 2014, 53, 11886-11889). Therefore, developing an MSR catalyst system that combines Gao Guangre conversion efficiency, high stability, and is completely free of precious metal dependence remains a significant challenge. For a non-noble metal system, to realize efficient and stable photo-thermal methanol pyrolysis hydrogen production, the material is required to have light absorption capacity covering the full spectrum,