2537-69-1Relevant articles and documents
Water Oxidation by Mononuclear Ruthenium Complex with a Pentadentate Isoquinoline-Bipyridyl Ligand
Vennampalli, Manohar,Liang, Guangchao,Webster, Charles Edwin,Zhao, Xuan
, p. 715 - 721 (2014)
Mononuclear ruthenium complexes with a pentadentate ligand, N,N-bis[(isoquinolin-1-yl)methyl][6-(pyridin-2-yl)pyridin-2-yl]methanamine (DIQ-Bpy), were synthesized and characterized by 1H NMR spectroscopy, elemental analysis, electrochemistry, and theoretical calculations. The oxidation of water by [Ru(DIQ-Bpy)(H2O)]2+ was observed in the presence of excess amounts of CeIV. Relative to [Ru(DPA-Bpy)(H2O)]2+ [DPA-Bpy = N,N-bis(2-pyridinylmethyl) -2,2-bipyridine-6-methanamine], the substitution of pyridine groups in DPA-Bpy with electron-withdrawing isoquinolines results in higher redox potential and lower activity for the oxidation of water by [Ru(DIQ-Bpy)(H2O)] 2+. A kinetic study of water oxidation by [Ru(DPA-Bpy)(H 2O)]2+ suggests a mononuclear pathway for the oxidation of water. The noncovalent interaction between isoquinoline groups in [Ru(DIQ-Bpy)(H2O)]2+, which favors the formation of dinuclear species, might account for the lower activity for water oxidation by [Ru(DIQ-Bpy)(H2O)]2+. Mononuclear Ru complexes with a pentadentate ligand, N,N-bis[(isoquinolin-1-yl)methyl][6-(pyridin-2-yl)pyridin- 2-yl]methanamine (DIQ-Bpy), were synthesized and characterized. The effects of isoquinoline groups on the electrochemistry and the activity of [Ru(DIQ-Bpy)(H2O)]2+ on water oxidation are discussed. Copyright
Elucidation of the Reaction Mechanism for Higherature Water Gas Shift over an Industrial-Type Copper-Chromium-Iron Oxide Catalyst
Polo-Garzon, Felipe,Fung, Victor,Nguyen, Luan,Tang, Yu,Tao, Franklin,Cheng, Yongqiang,Daemen, Luke L.,Ramirez-Cuesta, Anibal J.,Foo, Guo Shiou,Zhu, Minghui,Wachs, Israel E.,Jiang, De-En,Wu, Zili
supporting information, (2019/05/22)
The water gas shift (WGS) reaction is of paramount importance for the chemical industry, as it constitutes, coupled with methane reforming, the main industrial route to produce hydrogen. Copper-chromium-iron oxide-based catalysts have been widely used for the higherature WGS reaction industrially. The WGS reaction mechanism by the CuCrFeOx catalyst has been debated for years, mainly between a "redox" mechanism involving the participation of atomic oxygen from the catalyst and an "associative" mechanism proceeding via a surface formate-like intermediate. In the present work, advanced in situ characterization techniques (infrared spectroscopy, temperature-programmed surface reaction (TPSR), near-ambient pressure XPS (NAP-XPS), and inelastic neutron scattering (INS)) were applied to determine the nature of the catalyst surface and identify surface intermediate species under WGS reaction conditions. The surface of the CuCrFeOx catalyst is found to be dynamic and becomes partially reduced under WGS reaction conditions, forming metallic Cu nanoparticles on Fe3O4. Neither in situ IR not INS spectroscopy detect the presence of surface formate species during WGS. TPSR experiments demonstrate that the evolution of CO2 and H2 from the CO/H2O reactants follows different kinetics than the evolution of CO2 and H2 from HCOOH decomposition (molecule mimicking the associative mechanism). Steady-state isotopic transient kinetic analysis (SSITKA) (CO + H216O → CO + H218O) exhibited significant 16O/18O scrambling, characteristic of a redox mechanism. Computed activation energies for elementary steps for the redox and associative mechanism by density functional theory (DFT) simulations indicate that the redox mechanism is favored over the associative mechanism. The combined spectroscopic, computational, and kinetic evidence in the present study finally resolves the WGS reaction mechanism on the industrial-type higherature CuCrFeOx catalyst that is shown to proceed via the redox mechanism.
Confined Pt11+ Water Clusters in a MOF Catalyze the Low-Temperature Water–Gas Shift Reaction with both CO2 Oxygen Atoms Coming from Water
Rivero-Crespo, Miguel A.,Mon, Marta,Ferrando-Soria, Jesús,Lopes, Christian W.,Boronat, Mercedes,Leyva-Pérez, Antonio,Corma, Avelino,Hernández-Garrido, Juan C.,López-Haro, Miguel,Calvino, Jose J.,Ramos-Fernandez, Enrique V.,Armentano, Donatella,Pardo, Emilio
, p. 17094 - 17099 (2018/12/04)
The synthesis and reactivity of single metal atoms in a low-valence state bound to just water, rather than to organic ligands or surfaces, is a major experimental challenge. Herein, we show a gram-scale wet synthesis of Pt11+ stabilized in a confined space by a crystallographically well-defined first water sphere, and with a second coordination sphere linked to a metal–organic framework (MOF) through electrostatic and H-bonding interactions. The role of the water cluster is not only isolating and stabilizing the Pt atoms, but also regulating the charge of the metal and the adsorption of reactants. This is shown for the low-temperature water–gas shift reaction (WGSR: CO + H2O → CO2 + H2), where both metal coordinated and H-bonded water molecules trigger a double water attack mechanism to CO and give CO2 with both oxygen atoms coming from water. The stabilized Pt1+ single sites allow performing the WGSR at temperatures as low as 50 °C.
