Researcher Li Yaguang, Dr. Zhang Zhibo, Professor Ye Jinhua, AEM: Nickel single atom helps solar photothermal ammonia cracking to produce hydrogen - a new zero-carbon hydrogen production method [Article information] Nickel single atom helps solar photothermal ammonia cracking to

Researcher Li Yaguang, Dr. Zhang Zhibo, Professor Ye Jinhua , AEM: Nickel single atom helps solar photothermal ammonia cracking hydrogen production-new zero-carbon hydrogen production method

[Article information]

nickel single atom helps solar photothermal synthesis ammonia cleavage hydrogen production-new zero-carbon hydrogen production method

First author: Li Yaguang, Guan Qingqing, Huang Guangyao

Corresponding author: Researcher Li Yaguang, Dr. Zhang Zhibo, Professor Ye Jinhua

Unit: Hebei University , Japan National Institute of Materials , Guangdong Academy of Sciences New Materials

[Research background]

0 [Research background]

0 hydrogen storage density is high (17.8%), and the generated hydrogen gas does not contain carbon substances. Compared with hydrogen storage substances such as methanol , formic acid , etc., ammonia is the key carrier for building a zero-carbon hydrocarbon energy system. Ammonia cleavage hydrogen production is a strong endothermic reaction of , which requires a large amount of fossil energy, which not only generates a large amount of carbon dioxide emissions, but also limits the large-scale application of ammonia cleavage hydrogen production. Hydrogen production by solar photothermal ammonia cracking has the potential to solve its energy consumption problem, but large-scale ammonia cracking hydrogen production catalysts: the catalytic reaction temperature of Ni-based materials is 600-850°C, which is not possible with solar photothermal catalysis (usually 300-450°C). Therefore, the development of Ni-based catalysts with high catalytic activity in low operating temperature environments is the core issue of hydrogen production by solar photothermal ammonia cracking.

[Article Introduction]

Recently, Dr. Li Yaguang's research group from Hebei University cooperated with Dr. Zhang Zhibo from the Institute of New Materials of Guangdong Academy of Sciences and Professor Ye Jinhua from the National Institute of Materials of Japan to publish the title "Low Temperature Thermal and Solar Heating Carbon-Free Hydrogen Production from Ammonia Using Nickel Single Atom Catalysts” article. Through theoretical calculations, this article predicts that the nickel single atom can change the bonding mode of the nickel catalyst with NH3, thereby greatly reducing the hydrogen production temperature of NH3 cracking. The Ni single atom/CeO2 two-dimensional material (SA Ni/CeO2) was synthesized by the sol-gel method, and coupled it with the photothermal system, successfully achieving high-efficiency solar photothermal ammonia cracking hydrogen production.

Figure 1. Schematic diagram of hydrogen production caused by nickel single atoms that helps solar photothermal ammonia cracking.

[Big points of this article]

Key points 1: NH3 cleavage mechanism of nickel single atom

Theoretical calculation results show that Ni single atom has stronger NH3 adsorption capacity compared with Ni particles, which is conducive to NH3 reaction at Ni single atom sites. Not only that, the ammonia cleavage energy barrier at the Ni single atomic site is 1.21 eV, while the ammonia cleavage energy barrier of the Ni particles is 1.77 eV, indicating that ammonia cleavage is easier to produce hydrogen at the Ni single atomic site. Bader charge analysis showed that the charges of Ni single atom and Ni particles were +1.23 and +0.03|e|, respectively. The electronegative value difference shows that the coordination mode (Ni-N) between Ni single atom and Ni particles and the cracked nitrogen atom are ionic bonds and covalent bonds , respectively. Therefore, nitrogen atoms are more likely to desorption from Ni single atom sites, and NH3 preferentially dehydrogenated on Ni single atoms compared to Ni particles.

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Key points 2: Synthesis and Characterization of Ni single atoms

In order to prove that Ni single atoms have superior ammonia cracking hydrogen production activity, we used the sol-gel method to prepare Ni single atoms (SA Ni/CeO2) on CeO2 two-dimensional material. The material has a typical two-dimensional morphology. The spherical aberration correction scanning transmission electron mirror (HAADF-STEM) observed a bright spot with a size of ~0.1 nanometers on the lattice surface, indicating that there is a single atom , and further used synchronous radiation to prove that Ni elements are in SA The distribution state in Ni/CeO2 is a single-atom structure. Moreover, the specific surface area of ​​SA Ni/CeO2 is 187 m2 g-1, which can expose a large number of catalytic sites.

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Key points three: Low-temperature ammonia cracking of nickel single atoms hydrogen production

At present, the highest H2 productivity of nickel-based catalysts catalyzed ammonia cracking at 600°C is about 4 mmol g-1 min-1. In this article, at 300°C, the hydrogen production rate of SA Ni/CeO2 catalyzed NH3 cracking is 3.544 mmol g-1 min-1, which not only exceeds the best non- precious metal catalysts reported so far, but also has better performance than many precious metal catalysts, , while the hydrogen production rate of NH3 cracking of Ni particles is zero. In addition, SA Ni/CeO2 has good hydrogen production stability for NH3 cracking, and the H2 yield is almost constant in the catalytic NH3 cracking test at 300°C for 90 hours, at 3.5 mmol g-1 min-1.

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Key points 4: Nickel single atoms help solar photothermal ammonia cracking to produce hydrogen

Based on this, we coupled SA Ni/CeO2 with our homemade TiC/Cu-based photothermal system, and the temperature of SA Ni/CeO2 reaches 310°C under a standard solar irradiation . The SA Ni/CeO2 catalyst can be used for ammonia cracking and hydrogen production under 0.8 standard solar radiation. Under one standard solar radiation, the hydrogen production rate of ammonia cracking reaches 1.58 mmol g-1 min -1. This is more than 100 times the recorded rate of natural solar light-driven NH3 catalytic cracking and hydrogen production. It realizes the zero carbon emission of the full ammonia cracking hydrogen production system.

[Article link]

Low Temperature Thermal and Solar Heating Carbon-Free Hydrogen Production from Ammonia Using Nickel Single Atom Catalysts

https://doi.org/10.1002/aenm.202202459

[ Introduction to the corresponding author ]

Li Yaguang , researcher at Hebei University, winner of the Hebei Province Outstanding Youth Fund, and Kunyu Young Scholar. In 2015, he graduated from , School of Materials Science and Engineering, Zhejiang University, and later entered Hebei University to work. He is currently the leader of the research group of the photodriven catalytic research group. In recent years, he has been mainly engaged in research on photodriven catalysis. He presided over or participated in a number of scientific research projects such as the National Natural Science Foundation of China, the Hebei Natural Science Foundation of China Outstanding Youth/Excellent Youth Fund Project, the Hebei Provincial Department of Education’s Youth Outstanding Project, and the first or corresponding author has published more than 50 papers in academic journals such as Nat. Commun., Adv. Energy Mater., Nano Energy, Adv. Science, Appl. Catal. B., Green Chem., Small, J. Mater. Chem. A.; he has authorized 7 national invention patents.

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Zhang Zhibo , senior engineer at the Institute of New Materials, Guangdong Academy of Sciences, and vice president of Foshan Industrial Technology Research Institute of Guangdong Academy of Sciences. In 2018, he graduated from the Technical University of Kaiserslautern, Germany. During this period, he went to Davis, the University of California, USA as a visiting scholar. He later joined the Institute of New Materials, Guangdong Academy of Sciences and is currently an academic leader of the materials genetic engineering team. In recent years, it has been mainly engaged in multi-scale computing and big data direction of interface/surface. He presided over a number of scientific research projects such as the National Natural Science Foundation of China, the National Ministry of Science and Technology’s high-end foreign expert introduction program, the Guangdong Province Key Field R&D Program Sub-Project, and the Guangdong Province Enterprise Commissioner Project. He has published more than 30 papers in academic journals such as Nat. Commun., Adv. Energy Mater., Appl. Surf. Sci., Ceram. Int.; applied for 12 national invention patents and 1 software copyright.

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Leaf Golden Flower , Chief Researcher of NIMS, Professor of Hokkaido University, and Chief Scientist of 973 Project. Over the past 20 years, Professor Ye Jinhua's research team has been mainly engaged in the research and development of optical functional materials and its application research in the fields of environmental protection and new energy. It has successively undertaken more than a dozen major research projects including the Japanese government, industry, the national "973" project and the National Natural Science Foundation of China key projects. A number of internationally leading innovative achievements have been achieved.More than 550 high-quality papers have been published in internationally renowned journals such as Nature, Nat. Catal., Nat. Mater., Joule, Nat. Commun., Angew. Chem. Int. Ed., J. Am. Chem. Soc. and Adv. Mater. So far, it has received about 56,000 citations from its peers, with an H factor of 118. In 2016, it was selected as a member of the Royal Chemistry Society of the United Kingdom and was selected by Thomson Reuters as the global high-cited scientist of 2016, 2018, 2019, 2020 and 2021, serving as Catalys Science & Technology, Science Advanceds, Associate Editor of ACS Nano Magazine.