The 228th MANA & the 101st ICYS Joint Seminar
Dr. Yuanjian Zhang & Dr. Qingsong Mei
| Date | November 4, Friday |
| Time | 15:30-16:30 |
| Place | Seminar room #811, 8F, Central Bldg., Sengen Site, NIMS |
Download PDF file for seminar info.
15:30-16:00
Wet Chemical Synthesis of Nitrogen-Doped Carbon towards Sustainable Oxygen Reduction Electrocatalysts
The oxygen reduction reaction (ORR) is one of the important reactions not only in life process but also in artificial energy conversion systems, such as fuel cells and metal-air batteries. Due to the slow kinetics, ORR catalysts such as Pt-based materials are widely investigated, but how to prepare sustainable catalysts is still one long-term challenge. Thanks to unique electronic interactions between the lone-pair electrons of nitrogen and the Pi-system of graphitic carbon, nitrogen (N)-doped carbon nanostructures are among the most promising noble-metal free catalysts for ORR. However, N-doped carbon for ORR is commonly prepared by the pyrolysis/annealing at high temperature up to 1100 ?C. As chemists, we prefer controlling the chemical reactions as we like; however, in such high temperature, it is extremely difficult to control the reactions during the preparation of N-doped carbon. Therefore, development of ORR active N-doped carbon at low temperature is highly desired. Here, we will present our preliminary result addressing this challenge.
Speaker
Dr. Yuanjian Zhang, ICYS-MANA Researcher, NIMS
Chair
Dr. Toshiyuki Mori, Battery Materials Unit, NIMS
16:00-16:30
How the grains of metals are refined by plastic deformation: A study on Cu by surface rolling
When metals are subjected to plastic deformation, they response both microstructurally and mechanically: typically grain refinement for the former and strain hardening for the latter and the two are intrinsically related. Such behavior has been widely utilized to fabricate ultrafine-grained and nanostructured metals with the development of new processes to introduce large plastic deformation in recent years. However, despite the numerous experimental studies, the mechanism for such deformation-induced grain refinement is still not well understood. In this presentation, I will talk about our recent studies on Cu, and try to provide a general understanding of this problem based on previous results and our new findings.
Speaker
Dr. Qingsong Mei, ICYS-Sengen Researcher, NIMS
Chair
Dr. Koichi Tsuchiya, Structural Materials Unit, NIMS