scholarly journals Vibrational Dynamics of Carbon Monoxide at the Active Sites of Mutant Heme Proteins†

1996 ◽  
Vol 100 (29) ◽  
pp. 12100-12107 ◽  
Author(s):  
Jeffrey R. Hill ◽  
Dana D. Dlott ◽  
C. W. Rella ◽  
Kristen A. Peterson ◽  
Sean M. Decatur ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Heme Proteins ◽  
Active Sites ◽  
Vibrational Dynamics

scholarly journals CO Oxidation Efficiency and Hysteresis Behavior over Mesoporous Pd/SiO2 Catalyst

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 131 ◽  
Author(s):  
Rola Mohammad Al Soubaihi ◽  
Khaled Mohammad Saoud ◽  
Myo Tay Zar Myint ◽  
Mats A. Göthelid ◽  
Joydeep Dutta
Keyword(s):  
Carbon Monoxide ◽  
Catalytic Activity ◽  
Co Oxidation ◽  
Active Sites ◽  
Bond Activation ◽  
Dissociative Adsorption ◽  
High Catalytic Activity ◽  
Good Catalytic Activity ◽  
Pretreatment Conditions ◽  
Oxidation Efficiency

Carbon monoxide (CO) oxidation is considered an important reaction in heterogeneous industrial catalysis and has been extensively studied. Pd supported on SiO2 aerogel catalysts exhibit good catalytic activity toward this reaction owing to their CO bond activation capability and thermal stability. Pd/SiO2 catalysts were investigated using carbon monoxide (CO) oxidation as a model reaction. The catalyst becomes active, and the conversion increases after the temperature reaches the ignition temperature (Tig). A normal hysteresis in carbon monoxide (CO) oxidation has been observed, where the catalysts continue to exhibit high catalytic activity (CO conversion remains at 100%) during the extinction even at temperatures lower than Tig. The catalyst was characterized using BET, TEM, XPS, TGA-DSC, and FTIR. In this work, the influence of pretreatment conditions and stability of the active sites on the catalytic activity and hysteresis is presented. The CO oxidation on the Pd/SiO2 catalyst has been attributed to the dissociative adsorption of molecular oxygen and the activation of the C-O bond, followed by diffusion of adsorbates at Tig to form CO2. Whereas, the hysteresis has been explained by the enhanced stability of the active site caused by thermal effects, pretreatment conditions, Pd-SiO2 support interaction, and PdO formation and decomposition.

First-Principles DFT Insights into the Mechanisms of CO2 Reduction to CO on Fe (100)-Ni Bimetals

2021 ◽  
Author(s):  
Caroline Kwawu ◽  
Albert Aniagyei ◽  
Destiny Konadu ◽  
Elliot Menkah ◽  
Richard Tia
Keyword(s):  
Carbon Monoxide ◽  
Binding Site ◽  
Active Sites ◽  
Density Functional ◽  
Co2 Reduction ◽  
Density Functional Theory Calculations ◽  
Hydrocarbon Fuel ◽  
Generalized Gradient ◽  
Efficient Catalyst ◽  
Stepped Surface

Abstract Iron and nickel are known active sites in the enzyme carbon monoxide dehydrogenases (CODH) which catalyzes CO2 to CO reversibly. The presence of nickel impurities in the earth abundant iron surface could provide a more efficient catalyst for CO2 degradation into CO, which is a feedstock for hydrocarbon fuel production. In the present study, we have employed spin-polarized dispersion-corrected density functional theory calculations within the generalized gradient approximation to elucidate the active sites on Fe (100)-Ni bimetals. We sort to ascertain the mechanism of CO2 dissociation to carbon monoxide on Ni deposited and alloyed surfaces at 0.25, 0.50 and 1 monolayer (ML) impurity concentrations. CO2 and (CO + O) bind exothermically i.e., -0.87 eV and − 1.51 eV respectively to the bare Fe (100) surface with a decomposition barrier of 0.53 eV. The presence of nickel generally lowers the amount of charge transferred to CO2 moiety. Generally, the binding strengths of CO2 were reduced on the modified surfaces and the extent of its activation was lowered. The barriers for CO2 dissociation increased mainly upon introduction of Ni impurities which is undesired. However, the 0.5 ML deposited (FeNi0.5(A)) surface is promising for CO2 decomposition, providing a lower energy barrier (of 0.32 eV) than the pristine Fe (100) surface. This active 1-dimensional defective FeNi0.5(A) surface provides a stepped surface and Ni-Ni bridge binding site for CO2 on Fe (100). Ni-Ni bridge site on Fe (100) is more effective for both CO2 binding or sequestration and dissociation compared to the stepped surface providing the Fe-Ni bridge binding site.

Carbon Monoxide Binding by de Novo Heme Proteins Derived from Designed Combinatorial Libraries

2001 ◽  
Vol 123 (10) ◽  
pp. 2109-2115 ◽  
Author(s):  
David A. Moffet ◽  
Martin A. Case ◽  
John C. House ◽  
Kathleen Vogel ◽  
Robert D. Williams ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Heme Proteins ◽  
De Novo ◽  
Combinatorial Libraries ◽  
Carbon Monoxide Binding

Neopterin, Dihydroneopterin, Tetrahydroneopterin: Different Structures-Increasing Capacity Cleaving the Porphyrin in Heme Proteins

Pteridines ◽  
2002 ◽  
Vol 13 (4) ◽  
pp. 115-120 ◽  
Author(s):  
Renate Horejsi ◽  
Reinhard Möller ◽  
Erwin Tafeit ◽  
Gilbert Reibnegger
Keyword(s):  
Carbon Monoxide ◽  
Heme Proteins ◽  
Interferon Γ ◽  
Heme Iron ◽  
Oxygen Species ◽  
Subsequent Generation ◽  
Biological Stability ◽  
Human Macrophages ◽  
Non Heme Iron ◽  
Hydroxide Radicals

Abstract Neopterin, 7,8-dihydroneopterin and 5,6,7,8-terahydroneopterm are secreted by human macrophages after activation by interferon-γ. The biological stability of the reduced pterins is less than one hour and therefore distinctly lower than that of neopterin. Ptendme derivatives are known to act as enhancers as well as scavengers of radical mediated processes. The effects of the three pteridines were investigated on hemoglobin and myoglobin, biomolecules that generate reactive oxygen species themselves. The amounts of liberated carbon monoxide and non heme iron stemming from the cleaved porphyrin were quantified. Iron and carbon monoxide were yielded at equimolar concentrations with a con-elation coefficients greater 0.9. Dihydroneopterin and tetrahydroneopterin were assumed to reduce the heme iron in intact heme molecules creating the conditions for adducting carbon monoxide and additionally the subsequent generation of hydroxide radicals via autooxidation. The effect of neopterin under these experimental concentrations was rather weak.

Reactions of carbon with atomic gases

1959 ◽  
Vol 12 (4) ◽  
pp. 533 ◽  
Author(s):  
JD Blackwood ◽  
FK McTaggart
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Water Vapour ◽  
Active Sites ◽  
Atmospheric Temperature ◽  
Carbon Surface ◽  
Hydrogen Atoms ◽  
Different Temperatures ◽  
Atomic Species ◽  
Oxygen Groups

Wood chars were reacted at atmospheric temperature with hydrogen atoms, oxygen atoms and carbon monoxide, hydrogen atoms and hydroxyl radicals, produced by the action of a radio frequency field on hydrogen, carbon dioxide, and water vapour respectively. The chars were prepared at different temperatures and contained different amounts of oxygen. The experimental results showed that the gases must be present in the atomic form before reaction with the carbon can take place and that such species react on the carbon-surface independently of active sites. In normal gasification processes the atomic species appear to be produced at active centres, which for the chars used could be correlated with specific oxygen groups remaining in the carbon. It is suggested that these groupings may have a pyran structure. An explanation has been put forward for the retardation of the carbon-water vapour reaction by hydrogen, and of the carbon-carbon dioxide reaction by carbon monoxide. These are considered as due to reverse mechanisms which decrease the concentration of the atomic species and not to the blocking of active sites by adsorption of the retardant.

scholarly journals 3P096 Preparation of myoglobin mutants exhibiting preferential binding of oxygen over carbon monoxide(02. Heme proteins,Poster,The 52nd Annual Meeting of the Biophysical Society of Japan(BSJ2014))

2014 ◽  
Vol 54 (supplement1-2) ◽  
pp. S264
Author(s):  
Ryu Nishimura ◽  
Daichi Matsumoto ◽  
Tomokazu Shibata ◽  
Sachiko Yanagisawa ◽  
Takashi Ogura ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Annual Meeting ◽  
Heme Proteins ◽  
Biophysical Society ◽  
Preferential Binding
Sign in / Sign up

Export Citation Format

Share Document