Mingjie Li君が中心となって行った担持ルテニウムリン化物触媒による選択的CO2水素化に関する研究成果がEnrgy & Fuel誌 (ACS)にAcceptされました。Our paper reports the selective CO2 hydrogenation over supported Ru phosphide catalysts in Energy & Fuels (ACS).


「Phosphorus-Enhanced Ru/TiO2 Catalysts: A Leap in Selective CO2 to CO Conversion」

Li, Mingjie; Miura, Hiroki; Shishido, Tetsuya

Energy & Fuels, 2024,. DOI: 10.1021/acs.energyfuels.4c00666

The reverse water–gas shift (RWGS) reaction is a promising method of CO2 emission reduction because CO is a key intermediate in various catalytic processes used to produce fuels and chemicals. However, during the reaction, CH4 is easily formed by side reactions rendering the product separation of CO difficult. Hence, rationally designed catalysts for the RWGS process exhibiting exceptional CO selectivity while minimizing CH4 selectivity are highly desirable. Although considerable efforts have been made to control the selectivity of CO2 hydrogenation, achieving 100% CO selectivity remains a challenge. In this study, the selectivity of supported Ru catalysts prepared by a conventional impregnation method was remarkably altered by loading with phosphorus. The phosphorus-loaded Ru/TiO2 (Ru-xP/TiO2x = P/Ru molar ratio ≥ 2) catalysts promoted the RWGS reaction and suppressed CH4 formation, resulting in 100% selectivity for CO, despite the fact that the unmodified supported Ru catalyst (Ru/TiO2) exhibited high selectivity for CH4 instead of CO. Structural characterization revealed ruthenium phosphides, such as Ru2P, on the surfaces of the Ru-xP/TiO2 catalysts. The results of the kinetic analysis, CO hydrogenation, and H2–D2 exchange clearly showed that the reaction mechanism of CO2 hydrogenation over the Ru-xP/TiO2 catalysts was different from that over Ru/TiO2. We propose that the fraction of weakly adsorbed CO on the surface of Ru-xP/TiO2 catalysts is increased compared to Ru/TiO2, which explains the 100% CO selectivity. This study provides valuable insights into catalyst design with significant implications for industrial applications, particularly in transforming greenhouse gases into valuable products to mitigate climate change.