News from Nanotechjapan


High Performance Catalyst for Ammonia Synthesis Composed of Ru Nano-layer on Strongly Basic Pr2O3

 Oita University and Japan Science and Technology Agency (JST) announced on September 21, 2016 that a research group led by Associated Professor Katsutoshi Nagaoka at the university has developed a high performance catalyst for ammonia synthesis, which is composed of low-crystalline ruthenium (Ru) nano-layer supported on praseodymium oxide (Pr2O3) and is activated under mild condition. The research was supported by JST and details were published in Chemical Science *. 

 Ammonia is a crucial chemical feedstock for fertilizer production and is a potential carbon-free energy carrier. However, the current method of ammonia synthesis, the Haber-Bosch process, uses Fe-based catalyst and requires severe conditions of high pressure over 200 atmospheric pressure and high temperature over 450℃. In order to relax the condition, the research group developed Ru/Pr2O3 catalyst without any dopant to show 1.8 times the rates reported with other highly active catalysts under mild conditions such as 9 atmospheric pressure and 390℃.

 Scanning transmission electron micrograph (STEM) observations and energy dispersive X-ray analyses (EDXA) revealed the formation of low-crystalline nano-layers of Ru on the surface of Pr2O3. Furthermore, CO2 temperature-programmed desorption revealed that the catalyst was strongly basic. These unique structural and electronic characteristics are considered to synergistically accelerate the rate-determining step of NH3 synthesis, cleavage of the N-triple bond in N2 molecules.

*Katsutoshi Sato, Kazuya Imamura, Yukiko Kawano, Shin-ichiro Miyahara, Tomokazu Yamamoto, Syo Matsumura, and Katsutoshi Nagaoka, "A low-crystalline ruthenium nano-layer supported on praseodymium oxide as an active catalyst for ammonia synthesis", Chemical Science, 2016, Advance Article, DOI:  10.1039/C6SC02382G; First published online 19 Sep 2016