Surface characterization of supported Pt$z.sbnd;Ru bimetallic clusters using infrared spectroscopy

Carbon Nanotubes Supported Mono- and Bimetallic Pt and Ru Catalysts for Selective Hydrogenation of Phenylacetylene

“…Bimetallic Pt–Ru catalysts stand in a very interesting and well-studied class of materials because of their excellent catalytic properties in methanation, hydrogenolysis, and direct methanol fuel cells. , However, the structure–property relationship is less well established because of ill-defined structures in alloy, core–shell and mixtures of monometallic particles. For example, Gonzalez et al , reported that supported Pt–Ru bimetallic particles could be formed by coimpregnation and pretreatment in H 2 , while Esteban et al reported that partial phase segregation occurred in supported Pt–Ru catalysts under similar conditions. There also have been reports of a core–shell-type model with a Ru-rich core and a Pt-rich outer shell under similar conditions. − Finally, there is disagreement on whether an oxidation treatment before reduction results in increased interactions between Pt and Ru. − More recent reports on the Pt–Ru bimetallic catalyst have focused on their application as electrocatalysts for hydrogen oxidation due to their high activity − and high resistance to CO poisoning compared with conventional monometallic Pt.…”

“…8,9 However, the structure−property relationship is less well established because of ill-defined structures in alloy, core−shell and mixtures of monometallic particles. For example, Gonzalez et al 10,11 reported that supported Pt−Ru bimetallic particles could be formed by coimpregnation and pretreatment in H 2 , while Esteban et al 12 reported that partial phase segregation occurred in supported Pt−Ru catalysts under similar conditions. There also have been reports of a core−shell-type model with a Ru-rich core and a Pt-rich outer shell under similar conditions.…”

Identifying the Performance Descriptor in Direct Syngas Conversion to Long-Chain α-Olefins over Ruthenium-Based Catalysts Promoted by Alkali Metals

“…The red shift of the CO adsorption peak indicated that the alkali metal promoter as an electronic donor enriched the density of the electronic charge in the d orbitals protruding from the metal surface. This could lead to an increment in the degree of backdonation of the charge from these orbitals to the π* antibonding orbitals of the chemisorbed CO. , The red shift difference of CO linear adsorbed peaks further proved that different kinds of electron donor additives lead to different electron densities of metallic Ru, thereby reducing the amplitude of the carbonyl stretch vibration frequency.…”

Mn-Promoted Ru-Based Catalysts for Enhanced Fischer–Tropsch Synthesis of Olefins from Syngas

“…In addition, a gradual red-shift of the linearly adsorbed CO peaks was observed for Mn-promoted catalysts. The red-shift of the CO linear adsorption peak indicated that the Mn promoter enriched the density of electronic charge in the d orbitals protruding from the metal surface as the electron donor and an enhancement in the degree of back-donation of charge from these orbitals to the π* antibonding orbitals of chemisorbed CO. , The difference in the red-shift of CO linear adsorption peaks further proved that different Mn contents led to different electron densities of metallic Ru, thereby reducing the amplitude of the carbonyl stretch vibration frequency . However, compared to the Ru catalyst, there is a slight shift of the CO linear adsorption peaks to higher wavenumbers with increasing Mn content, suggesting that the electron density was reduced and excessive Mn loading restrained the CO chemisorption.…”