Novel Single Atom Synergistic Catalyst Approach

image: Synergistic catalyst of single atoms and nanoparticles of iridium exhibits unprecedented activity for the hydrogenation of quinoline.
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The key to chemical reactions is in the name – there has to be something that makes the chemicals react with each other. Called a catalyst, this component induces or speeds up reactions in a controlled manner to produce the desired result. The catalysts used in several industries are often composed of noble metals, which are not efficient enough to compensate for their high cost. To solve this problem of the chemical reaction of adding hydrogen, called hydrogenation, to quinoline, an important molecule in pharmaceutical production, researchers based in China have developed a highly efficient catalyst comprising synergistic nanoparticles and single atoms of ‘iridium.

They published their approach on March 22 in Nano-research.

“Selective hydrogenation of quinoline and its derivatives into corresponding products has wide applications in fine chemical and pharmaceutical industry,” said co-corresponding author Changyan Cao, a researcher at the Institute of Chemistry, at the Chinese Academy of Sciences (ICCAS) and Chinese Academy University. of Science (UCAS). “Quinolines are an important class of compounds for accessing the tetrahydroquinoline products found widely in drug molecules, but noble metal catalysts are usually required to produce this reaction. As such, it is very important to improve the activity and efficiency of using precious metals due to their high price.

The researchers focused on single-atom catalysts, which Cao says have become a hot topic in catalysis because of how they can merge the advantages of homogeneous and heterogeneous catalysts. Homogeneous catalysts promote a uniform reaction, but heterogeneous catalysts can induce a reaction with higher yield. The problem, according to Cao, is that single-atom catalysts don’t have a metal-to-metal bond. Without this bond to fuse with, the hydrogen is forced through a different pathway which results in less overall hydrogenation.

“Since hydrogen more easily dissociates into matching pairs on noble metal nanoparticles – into hydrogen atoms, for example – and it is well known that hydrogen atoms propagate, we emitted the hypothesis that the hydrogen atoms formed on the metal nanoparticles could also migrate to unique metal sites for hydrogenation,” Cao said, explaining that the initial hydrogenation activity between the proposed catalyst and the substrate would essentially produce a secondary phase of hydrogen atoms capable of continuing the catalysis process.”By such a design, the problems mentioned above could be solved.”

To design such a catalyst, the researchers dispersed single atoms of iridium – the noble metal with the highest reported intrinsic activity for the hydrogenation of quinoline – and nanoparticles in a carbon support. When quinoline was applied, the reaction was found to be more efficient than when only iridium atoms or nanoparticles were used.

“Building a synergistic catalyst changes the reaction pathway to take advantage of single-atom sites in substrate activation and nanoparticles in hydrogen dissociation,” said co-corresponding author Weiguo Song. , professor at ICCAS and UCAS. “All of these characteristics together contribute to the significantly improved hydrogenation performance compared to the homologous single atom catalyst and the nanoparticle catalyst alone.”

Although the synergistic catalyst developed does not eliminate the need for noble metals, it does reduce the amount needed for a better reaction.

“We have proposed and confirmed an effective strategy to stimulate catalytic activity for the hydrogenation of quinoline by constructing a synergistic catalyst of single atoms and iridium nanoparticles, solving the activity limitations of single atom catalysts “Song said. “Next, we will extend our research to other metal catalysts and hydrogenation reactions to demonstrate the universality of synergistic catalysis.”

Other contributors include Qikai Shen, Hongqiang Jin and Peipei Li, ICCAS and UCAS; Xiaohu Yu, Institute of Theoretical and Computational Chemistry, Shannxi University of Technology; and Lirong Zhang, Beijing National Laboratory for Condensed Matter Physics, CAS Institute of Physics.

The National Natural Science Foundation of China, China National Key Research and Development Program, CAS Youth Innovation Promotion Association and Shaanxi National Basic Science Program supported this research.


On Nano-research

Nano-research is an international and interdisciplinary peer-reviewed research journal, sponsored by Tsinghua University and the Chinese Chemical Society. It offers readers an engaging mix of comprehensive, authoritative reviews and cutting-edge original research articles. After more than 10 years of development, it has become one of the most influential academic journals in the field of nanos. Quick review to ensure quick release is a key feature of Nano-research. In 2020 InCites Journal Citation Reports, Nano-research has an impact factor of 8.897 (8.696, 5 years), the total number of citations reached 23,150 and the number of highly cited articles reached 129, ranked in the top 2.5% of more than 9,000 journals academics, ranking first among China’s international academic journals.

On Tsinghua University Press

Founded in 1980, owned by Tsinghua University, Tsinghua University Press (TUP) is one of the leading comprehensive professional and higher education publishers in China. Committed to building a high-level global cultural brand, after 41 years of development, TUP has established an outstanding management system and corporate structure, and delivered multi-media and multi-dimensional publications covering books, audio, video, electronic products, magazines and digital publications. . Additionally, TUP is actively leading its strategic transformation from educational publishing to content development and service for teaching and learning and was named a National First Class Publisher for achieving outstanding results.

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Irene B. Bowles