A Kinetic Study on the Adsorption and Reaction of Hydrogen over Silica-Supported Ruthenium and Silver–Ruthenium Catalysts during the Hydrogenation of Carbon Monoxide

摘要: The simultaneous adsorption and reaction of hydrogen with preadsorbed carbon monoxide was investigated over a series silica-supported ruthenium silver-ruthenium bimetallic catalysts to elucidate the role site sensitivity on methane formation. specific rate synthesis, which is direct measure catalyst activity toward Fischer-Tropsch measured at 460 Torr temperatures from 400 500 K, varied 0.01 x 10{sup {minus}3} 3 {minus}3}S{sup {minus}1}. As little as 3% Ag reduced methanation Ru by 80%. temperature dependence turnover frequency showed that apparent activation energy for dropped 24 kcal/mol monometallic case 18 case. Since silver does not adsorb or react either monoxide, these results show act merely dilutant in system. These observations are elucidated terms new model surface-sensitive adsorption, termed portal mediated where low-coordination edge corner sites surface sinks rapid, dissociative weakly bound, highly mobile hydrogen. In situ {sup 1}H-NMR measurements ofmore » coverages during were used confirm kinetic treatment data.« less