Recently, the research group of Meng Gu, associate professor of the Department of Materials Science and Engineering of Southern University of Science and Technology (“the Department of Materialsâ€), and the research group of Feng Zhenxing, a scholar of Oregon State University, have made new progress in the field of nanomaterials and prepared ultra-high activity Ir-CoOx NSs, related results were published in ACS Catalysis.
The widespread use of petrochemical energy has caused the concentration of carbon dioxide in the atmosphere to rise linearly and cause a lot of pollution. The development and utilization of clean energy can effectively reduce greenhouse gas emissions and promote the realization of the goal of "carbon neutrality". Hydrogen has the characteristics of high energy density and zero emissions during use. At present, in a variety of high-efficiency hydrogen production methods such as photolysis of water, biological hydrogen production, hydrogen production by electrolysis and hydrogen production by pyrolysis, hydrogen production by electrolysis has the advantages of single product, no pollution in the preparation process, and few environmental constraints. Therefore, it may become the most potential industrial hydrogen production method. However, the anode oxygen evolution reaction (OER) required for the electrolysis of water to hydrogen is too high, and the cost of commercial catalysts is too high, which greatly limits the efficiency of hydrogen production and increases the cost of hydrogen production. This paper proposes a new single-atom catalyst strategy to deposit iridium (Ir) single atoms on the surface of ultra-thin amorphous cobalt oxide nanosheets (CoOx NSs), which improves the OER efficiency by two orders of magnitude compared to commercial catalysts. ; At the same time, the in-situ synchrotron radiation technique was used to observe the real-time changes of the catalyst during the reaction process, revealing the synergy mode of the multi-element catalyst in the anodization process. The research has greatly promoted the application of basic science and engineering, and has shown certain practical significance.
Figure 1. Structural characterization of the catalyst. (Ac) CoOx NSs base. The embedded icon shows the diffusion band of the selected area. (Df) Structural characterization of Ir-CoOx NSs. The red circle marks the Ir single atom. The Ir/Co ratio is about 7:93, and the Ir atomic load is about 20% by mass.
The overpotential of the catalyst in the OER process is only 150 mV, and its current density is 160 times that of the commercial catalyst iridium dioxide. The deposition of monoatomic Ir can effectively increase the electrochemical area of ​​the catalyst, thereby greatly improving the performance of OER. In addition, the deposition of Ir single atoms greatly improves the mass transfer efficiency of the catalyst. These features ensure that the catalyst has a very high energy utilization efficiency, thereby effectively improving the electricity utilization efficiency of the entire system of electrolyzed water. In addition, the stability test results show that the structure of the catalyst is relatively stable during the OER process, and at the same time, the resistance to large working current is outstanding. The results of the in-situ synchrotron radiation study show that the catalyst has an overpotential starting potential of less than 30mV, which explains the source of the high intrinsic activity of the catalyst. Furthermore, the Ir-O-Co formed in situ is the real active site, and O in this coordination system tends to be closer to the Ir atom. In the catalytic process, Ox- near Ir is preferentially oxidized to oxygen, and an orderly and efficient OER process is realized.
Figure 2. Electrochemical test results. OER polarization curve (a), (bc) OER performance comparison, electric double layer capacitance test (e) and mass transfer efficiency analysis (f).
Cai Chao, the first author of the paper and a PhD student in the Department of Materials Science and Technology of SUSTech, said that unlike the transition metal-based OER catalysts that are currently very hot in research, the Ir single atom has a high degree of discrimination in the catalyst system, so it is easier to obtain reliable results using in-situ technology Characterization results. This is of great help for the in-depth study of the working mechanism of OER catalyst in the reaction process, including the analysis of the structure evolution of the catalyst and the confirmation of the true activity. At the same time, it will have a certain enlightening effect on obtaining catalysts that are more efficient, lower cost, and more resistant to high voltage or high current. The research group will conduct further research in the direction of water electrolysis, and contribute to the realization of the goal of "carbon neutrality".
Doctoral student Wang Maoyu and visiting student Han Shaobo from the Department of Materials Science and Technology of SUSTech are the co-first authors of the paper. Zu Xiaotao from the University of Electronic Science and Technology of China, Feng Zhenxing and Gu Meng from Argonne State University are the co-corresponding authors of the paper. Other authors include SUSTech Wang Qi, Zhang Qing, Zhu Yuanmin, Yang Xuming, Wu Duojie and George E. Sterbinsky, Argonne National Laboratory. The research has received strong support from the National Natural Science Foundation of China, Guangdong Provincial Key Laboratory of Electric Power Drive, Guangchuang Project, Shenzhen Peacock Project, Shenzhen Engineering Research Center, Shenzhen Clean Energy Center and other units.
2D Panel Fence
- 1. Because of the simple, beautiful and practical grid structure of double wire mesh fence, it has the function of beautifying the environment. In addition, combined with the characteristics of double wire mesh fence which is easy for plants to climb, it is used for the beautification effect of parks and living communities. - 2. The price of double wire mesh fence net is medium and low, and it is often used for the protection of industrial land, sports field, playground, school and nursery.
2D Panel Fence,Wire Fence Panels,Mesh Double Wire Fence,Double Wire Fence Panels
HeBei Bosen Metal Products Co.,Ltd , https://www.hbbosenfence.com