メタン活性化に関する九州大学、産総研、北九州市立大との共同研究の成果がCatalysis Science & Technology誌 (RSC)にAcceptされました。Our collaboration with Kyusyu Univ. AIST, and Kitakyusyu City Univ. was accepted in Catalysis Science & Technology誌 (RSC).
「Insights into Pt–CN species on an alumina-supported platinum catalyst as active intermediates or inhibitors for low-temperature hydrogen cyanide synthesis from methane and nitric oxide」.
Takagaki, Atsushi; Bando, Kyoko; Yamasaki, Tatsuya; Murakami, Junichi; Suganuma, Nobuya; Ghampson, Isaac Tyrone; Kodaira, Tetsuya; Ishihara, Tatsumi; Shishido, Tetsuya
Catalysis Science & Technology, 2023,13, 5017-5024. DOI: 10.1039/D3CY00581J
Methane (CH4) was converted to hydrogen cyanide (HCN) at temperatures from 300 to 425 °C using a commercial 5 wt% Pt/Al2O3 catalyst with nitric oxide (NO) as an oxidant. HCN yield of ca. 1% was maintained after 100 h at 400 °C, whereas the yield was increased to 3.2% at 425 °C but rapidly decreased, resulting in 0.24% after 90 h at 425 °C. In situ X-ray absorption fine structure (XAFS) and Fourier-transform infrared (FTIR) measurements showed that Pt–CN species emerged and the extent of the adsorbed species roughly correlated with the production of HCN. However, the Pt–CN species continuously accumulated at higher temperatures than 400 °C regardless of the catalytic activity. The experiment of purging using helium gas followed by hydrogen after the reaction of CH4 and NO at 425 °C showed that the Pt–CN species were strongly adsorbed on the Pt catalyst and removed from the catalyst by hydrogen treatment with simultaneous formation of HCN and NH3. This study revealed that the Pt–CN species can function not only as important reaction intermediates, but also as inhibitors of the reaction. An appropriate balance of Pt–CN species and hydrogen species over the Pt surface is required to produce HCN continuously.
