Active sites are at the heart of catalysts, while the nature of active sites plays a key role in the performance of catalysts. During the past decade, the active sites of transition metal–nitrogen–carbon (TMNC) catalysts have not been well identified and are simply defined as TM-Nxbased on information from X-ray photoelectron spectroscopy (XPS). Such rough recognition of active sites leads to ambiguous understanding of the reaction mechanisms occurring on the surface of the catalysts, as well as stagnation of the development of rational catalyst design strategies. Recently, synchrotron radiation-based extended X-ray absorption fine structure (EXAFS) spectrum analysis, along with experimental characterization and theoretical simulation, has gradually been introduced to identify the geometric structures of active sites. Despite this progress, however, the more structurally sensitive X-ray absorption near edge structure (XANES) spectrum analysis has been neglected. To obtain fundamental understanding of active sites and catalytic mechanisms, identifying the electronic and geometric structures of active sites with both XANES and EXAFS spectra is still highly desired.
On June 13, 2019, the study entitled " Identifying the structure of Zn-N2active sites
and structural activation" was published online in Nature Communications (https://www.nature.com/articles/s41467-019-10622-1).The research was completed by Prof. Yunfei Bugroup of Nanjing University of Information Engineering in cooperation with Ulsan National Institute of Science and Technology of South Korea, University of Science and Technology of China, Jiangsu University and Nanjing University of Science and Technology.
In this study, Zn-N2active sites have been achieved and identified by both EXAFS and XANES spectra. Theoretical calculations reveal that the structural activation of oxygen species on Zn-N2active sites is favoured by the selective oxygen reduction, which is confirmed by the experimental results. This work not only achieves the preparation and identification of Zn-N2active sites but also provides a regular principle to obtain deep insight into the nature of catalysts for various catalytic applications.
Professor Yunfei Bu from the School of Environmental Science and Engineering at Nanjing University of Information Science & Technology, Professor Zhengping Fu from University of Science and Technology of China and Professor Jong-Beom Baek and Professor Hu Young Jeong from Ulsan National Institute of Science and Technology of South Korea were the co-corresponding authors. Dr. Feng Li from Ulsan National Institute of Science and Technology of South Korea was the first author of the paper.
