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CN-121990522-A - MgH (MgH)2Base composite hydrogen storage material and preparation method thereof

CN121990522ACN 121990522 ACN121990522 ACN 121990522ACN-121990522-A

Abstract

The invention discloses an MgH 2 -based composite hydrogen storage material and a preparation method thereof, belonging to the technical field of energy sources and energy conservation. The Fe 2 O 3 /TiO 2 catalyst has the hydrogen-repellent characteristic of Fe and the hydrogen-philic characteristic of Ti, forms a bidirectional synergistic catalytic effect, and the ball-rod porous structure can improve hydrogen diffusion conditions and prevent MgH 2 agglomeration, the hydrogen absorption and desorption activation energy of the obtained composite is obviously reduced, the kinetic rate is fast, the hydrogen absorption and desorption of the composite is about 5.48wt.% in1 minute at 300 ℃, the hydrogen desorption is about 6.50wt.% in 10 minutes, the initial hydrogen storage capacity of 83.46% is still maintained after 90 times of circulation, the thermodynamic property is stable, and the application prospect in the solid hydrogen storage field is wide.

Inventors

  • DING CHAO
  • JIANG HAN
  • CHEN YUAN
  • ZHOU XIANG
  • WANG JINGFENG
  • PAN FUSHENG

Assignees

  • 重庆新型储能材料与装备研究院

Dates

Publication Date
20260508
Application Date
20251217

Claims (7)

  1. 1. The MgH 2 -based composite hydrogen storage material is characterized by comprising 94% of MgH 2 by mass and 6% of Fe 2 O 3 /TiO 2 composite catalyst by mass, wherein the Fe 2 O 3 /TiO 2 composite catalyst is a microsphere with a porous sphere-rod-shaped structure.
  2. 2. The MgH 2 -based composite hydrogen storage material according to claim 1, wherein the Fe 2 O 3 /TiO 2 composite catalyst has a multiphase interface structure formed by Fe-O-Ti bond bridging.
  3. 3. A method for preparing the MgH 2 -based composite hydrogen storage material according to claim 1 or 2, comprising the steps of: (1) Preparing a precursor solution, namely weighing 5mmol (NH 4 ) 2 TiF 6 and 9mmol CO (NH 2 ) 2 , adding into 50mL deionized water, and magnetically stirring until the solution is completely dissolved to obtain a transparent solution; (2) An iron source was added to prepare a 0.2M FeCl 3 solution 50: 50 mL. Dropwise adding the FeCl 3 solution into the transparent solution obtained in the step (1), continuously stirring, and then performing ultrasonic treatment on the solution for 20: 20 min to obtain a uniform mixed solution; (3) Transferring the mixed solution into a 100 mL Teflon lining high-pressure reaction kettle, performing hydrothermal treatment at 140 ℃ for 12 hours, and naturally cooling to room temperature after the reaction is finished; (4) Removing supernatant in the liner of the reaction kettle, centrifuging the residual turbid suspension, removing supernatant, adding deionized water for redispersion, and centrifuging again for washing for 3 times, placing the obtained solid in a blast drying oven, and drying 12 h at 60 ℃ to obtain Fe 2 O 3 /TiO 2 powder with a porous sphere-rod structure; (5) Weighing 0.94g of MgH 2 and 0.06g of Fe 2 O 3 /TiO 2 powder prepared in the step (4), and placing the powder and 10g of ball-milling beads in a ball-milling tank; (6) Ball milling and compounding, namely transferring a ball milling tank into a high-energy ball mill, and performing ball milling in a protective atmosphere; (7) And (3) collecting a product, namely transferring the ball milling tank into a glove box after ball milling, and taking out a sample to obtain the MgH 2 -based composite hydrogen storage material.
  4. 4. The method of claim 3, wherein the FeCl 3 solution in step (2) is prepared by weighing 1.35g FeCl 3 ·6H 2 O and dissolving in 50 mL deionized water.
  5. 5. A production method according to claim 3, wherein the centrifugation in the step (4) is centrifugation at 10000 r/min for 5: 5 min.
  6. 6. A method of preparation according to claim 3, wherein the protective atmosphere in step (6) is an argon atmosphere.
  7. 7. The method according to claim 3, wherein the ball milling process in the step (6) has the technological parameters of ball-to-material ratio of 10:1, and the batch ball milling process is adopted, ball milling is carried out for 10 minutes, suspension is carried out for 10 minutes, and total ball milling time is 16 hours.

Description

MgH 2 -based composite hydrogen storage material and preparation method thereof Technical Field The invention belongs to the technical field of energy and energy conservation, and relates to an MgH 2 -based composite hydrogen storage material and a preparation method thereof. Background MgH 2 has a higher theoretical hydrogen storage capacity (7.6 wt.%) and is considered to be one of the most potential solid hydrogen storage materials. However, the problems of high hydrogen absorption and desorption temperature, slow reaction kinetics, poor cycle stability and the like restrict the development of the magnesium-based energy storage material. In order to improve the hydrogen storage performance, researchers have proposed various modification strategies including catalysis, alloying, nanocrystallization, compounding and other methods. The catalytic modification is a simple and effective way, and the catalyst such as transition metal is introduced into the system, so that the reaction activation energy can be obviously reduced, and the hydrogen absorption and desorption rate of Mg/MgH 2 can be accelerated. However, a single metal catalyst can only play a promoting role on the side of hydrogen absorption or hydrogen release, so that bidirectional catalysis is difficult to perform on the catalyst and the overall hydrogen storage cycle performance is difficult to improve. Therefore, developing a composite catalytic system with multiphase interfaces and hydrogen-philic and hydrogen-phobic bimetal synergistic catalysis becomes a key for improving the hydrogen storage performance of Mg/MgH 2. The invention provides an MgH 2 -based composite hydrogen storage material and a preparation method thereof, which remarkably improve the hydrogen absorption and desorption kinetics and the circulation stability of magnesium hydride by introducing a nano porous sphere-rod junction Fe 2O3/TiO2 heterogeneous catalyst. Disclosure of Invention In order to achieve the technical purpose and achieve the technical effect, the invention provides the following technical scheme: The MgH 2 -based composite hydrogen storage material consists of 94% of MgH 2 and 6% of Fe 2O3/TiO2 composite catalyst, wherein the Fe 2O3/TiO2 composite catalyst is a microsphere with a porous sphere-rod structure. Preferably, the Fe 2O3/TiO2 composite catalyst has a multiphase interface structure formed by Fe-O-Ti bond bridge connection. On the other hand, the invention also provides a preparation method of the MgH 2 -based composite hydrogen storage material, which comprises the following steps: (1) Preparing a precursor solution, namely weighing 5mmol (NH 4)2TiF6 and 9mmol CO (NH 2)2, adding into 50mL deionized water, and magnetically stirring until the solution is completely dissolved to obtain a transparent solution; (2) An iron source was added to prepare a 0.2M FeCl 3 solution 50: 50 mL. Dropwise adding the FeCl 3 solution into the transparent solution obtained in the step (1), continuously stirring, and then performing ultrasonic treatment on the solution for 20: 20 min to obtain a uniform mixed solution; (3) Transferring the mixed solution into a 100 mL Teflon lining high-pressure reaction kettle, performing hydrothermal treatment at 140 ℃ for 12 hours, and naturally cooling to room temperature after the reaction is finished; (4) Removing supernatant in the liner of the reaction kettle, centrifuging the residual turbid suspension, removing supernatant, adding deionized water for redispersion, and centrifuging again for washing for 3 times, placing the obtained solid in a blast drying oven, and drying 12 h at 60 ℃ to obtain Fe 2O3/TiO2 powder with a porous sphere-rod structure; (5) Weighing 0.94g of MgH 2 and 0.06g of Fe 2O3/TiO2 powder prepared in the step (4), and placing the powder and 10g of ball-milling beads in a ball-milling tank; (6) Ball milling and compounding, namely transferring a ball milling tank into a high-energy ball mill, and performing ball milling in a protective atmosphere; (7) And (3) collecting a product, namely transferring the ball milling tank into a glove box after ball milling, and taking out a sample to obtain the MgH 2 -based composite hydrogen storage material. Preferably, the FeCl 3 solution in step (2) is prepared by weighing 1.35g FeCl 3·6H2 O and dissolving in 50 mL deionized water. Preferably, the centrifugation in step (4) is performed under conditions of 10000 r/min for centrifugation 5 min. Preferably, the protective atmosphere in the step (6) is an argon atmosphere. Preferably, the ball milling process in the step (6) has the technological parameters of ball-to-material ratio of 10:1, and adopts an intermittent ball milling process to perform ball milling for 10 minutes, and pauses for 10 minutes, wherein the total ball milling time is 16 hours. Compared with the prior art, the invention has the beneficial effects that: The Fe 2O3/TiO2 nano porous catalyst is constructed by a one-step hydrothermal method, and the pre