scholarly journals Doped Ceria Catalyst System: Catalyzing Carbon Monoxide Transformation (A-Review)

2021 ◽  
Vol 37 (6) ◽  
pp. 1262-1279
Author(s):  
Mayankkumar Lakshmanbhai Chaudhary ◽  
Rawesh Kumar
Keyword(s):  
Carbon Monoxide ◽  
Electronic Structure ◽  
Surface Energy ◽  
Co Oxidation ◽  
Surface Property ◽  
Catalyst System ◽  
Doped Ceria ◽  
Metal Metal ◽  
Redox Switching ◽  
Mobile Oxygen

As ceria chemistry broadens, it is needed to generalize the behavior of ceria surfaces towards molecules for carrying out a reaction. The endowing capacity of mobile oxygen due to rapid redox switching between Ce+4/Ce+3 is a key point for ceria containing surfaces. Herein we have presented a review which is broadly divided into two parts. First part focuses on surface property as how electronic structure, vacancy and surface energy would be modified after interaction of ceria with dopant (noble metal, metal of variable oxidation state, higher valent metal and lower valent metal). The second part focuses on catalysis as how the doped ceria surface influences the carbon monoxide transformations (CO oxidation, CO and H2O reaction, CO and NO reaction, CO and H2 reaction). This through study will be helpful to predict the ceria surface for a designed reaction.

scholarly journals Copper doped ceria porous nanostructures towards a highly efficient bifunctional catalyst for carbon monoxide and nitric oxide elimination

2015 ◽  
Vol 6 (4) ◽  
pp. 2495-2500 ◽  
Author(s):  
Shanlong Li ◽  
Nengli Wang ◽  
Yonghai Yue ◽  
Guangsheng Wang ◽  
Zhao Zu ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Carbon Monoxide ◽  
Co Oxidation ◽  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Bifunctional Catalyst ◽  
Catalytic Performance ◽  
Doped Ceria ◽  
Reduction Of No ◽  
Porous Nanomaterials

Cu2+ doped CeO2 porous nanomaterials were synthesized by calcining CeCu–MOF nanocrystals. They exhibited a superior bifunctional catalytic performance for CO oxidation and selective catalytic reduction of NO.

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.

scholarly journals Unique structure of active platinum-bismuth site for oxidation of carbon monoxide

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Bing Nan ◽  
Qiang Fu ◽  
Jing Yu ◽  
Miao Shu ◽  
Lu-Lu Zhou ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Low Temperature ◽  
Co Oxidation ◽  
Density Functional ◽  
Technology Development ◽  
Co Adsorption ◽  
Combustion Engines ◽  
Advanced Combustion ◽  
Surface Metal ◽  
Bismuth Cluster

AbstractAs the technology development, the future advanced combustion engines must be designed to perform at a low temperature. Thus, it is a great challenge to synthesize high active and stable catalysts to resolve exhaust below 100 °C. Here, we report that bismuth as a dopant is added to form platinum-bismuth cluster on silica for CO oxidation. The highly reducible oxygen species provided by surface metal-oxide (M-O) interface could be activated by CO at low temperature (~50 °C) with a high CO2 production rate of 487 μmolCO2·gPt−1·s−1 at 110 °C. Experiment data combined with density functional calculation (DFT) results demonstrate that Pt cluster with surface Pt−O−Bi structure is the active site for CO oxidation via providing moderate CO adsorption and activating CO molecules with electron transformation between platinum atom and carbon monoxide. These findings provide a unique and general approach towards design of potential excellent performance catalysts for redox reaction.

Mechanism of CO oxidation by carbon monoxide dehydrogenase from Clostridium thermoaceticum and its inhibition by anions

Biochemistry ◽  
1995 ◽  
Vol 34 (24) ◽  
pp. 7879-7888 ◽  
Author(s):  
Javier Seravalli ◽  
Manoj Kumar ◽  
Wei-Ping Lu ◽  
Stephen W. Ragsdale
Keyword(s):  
Carbon Monoxide ◽  
Co Oxidation ◽  
Carbon Monoxide Dehydrogenase ◽  
Clostridium Thermoaceticum

Adaptive Carbon Monoxide Kinetics for Exhaust Aftertreatment Modeling

2009 ◽  
Author(s):  
Christopher Depcik ◽  
Sudarshan Loya ◽  
Anand Srinivasan
Keyword(s):  
Carbon Monoxide ◽  
Co Oxidation ◽  
Oxidation Mechanism ◽  
Kinetic Mechanism ◽  
Combustion Efficiency ◽  
Platinum Group Metals ◽  
Catalyst Loading ◽  
Low Temperature Combustion ◽  
Inlet Conditions ◽  
Ci Engines

Future emission standards are driving the need for advanced control of both Spark (SI) and Compression Ignition (CI) engines. However, even with the implementation of cooled Exhaust Gas Recirculation and Low Temperature Combustion (LTC), it is unlikely that in-cylinder combustion strategies alone will reduce emissions to levels below the proposed standards. As a result, researchers are developing complex catalytic aftertreatment systems to meet these tailpipe regulations for both conventional and alternative combustion regimes. Simulating these exhaust systems requires fast and accurate models suitable for significant changes in inlet conditions. Most aftertreatment devices contain Platinum Group Metals because of their widely documented beneficial catalysis properties; examples include Diesel Oxidation Catalysts, Three-Way Catalysts and Lean NOx Traps. There are kinetic mechanisms available for each of these devices, but often they do not extrapolate well to other formulations. For example, Carbon Monoxide (CO) levels entering a catalyst are significantly different between an SI and CI engine. In addition, modifying engine control to utilize LTC operation can result in an increase in CO levels due to lower combustion efficiency. This adversely affects the conversion capabilities of a catalytic device through increased levels of CO inhibition. Finally, catalyst loading and metal dispersion differences between devices often prohibit a direct extension of kinetic constants. As a result, mechanisms often need recalibration for correct modeling capabilities. In order to begin creating a more predictive kinetic mechanism, this paper simulates CO oxidation as a function of different inlet concentration levels and metal loadings. While aftertreatment devices contain many reactions, modeling of one fundamental reaction is a first step to determine the feasibility of adaptive kinetics. In addition, research into the history of the CO oxidation mechanism over platinum illustrates a more accurate rate expression to utilize in deference to current modeling activities. The authors calibrate this expression to experimental data taking into account significant changes in inlet conditions, metal loading and dispersion values. Model fidelity is determined through the simulation of additional data not part of the initial calibration efforts. In addition, the paper discusses strengths and weaknesses of the model along with how other researchers can help foster adaptive kinetic development.

scholarly journals Insight into Energy Conservation via Alternative Carbon Monoxide Metabolism inCarboxydothermus pertinaxRevealed by Comparative Genome Analysis

2018 ◽  
Vol 84 (14) ◽  
Author(s):  
Yuto Fukuyama ◽  
Kimiho Omae ◽  
Yasuko Yoneda ◽  
Takashi Yoshida ◽  
Yoshihiko Sako
Keyword(s):  
Carbon Monoxide ◽  
Co Oxidation ◽  
Gene Cluster ◽  
Genome Analysis ◽  
Transcriptional Analysis ◽  
Comparative Genome Analysis ◽  
Co Dehydrogenase ◽  
Comparative Genome ◽  
Content Type ◽  
Energy Converting

ABSTRACTCarboxydothermusspecies are some of the most studied thermophilic carboxydotrophs. Their varied carboxydotrophic growth properties suggest distinct strategies for energy conservation via carbon monoxide (CO) metabolism. In this study, we used comparative genome analysis of the genusCarboxydothermusto show variations in the CO dehydrogenase-energy-converting hydrogenase gene cluster, which is responsible for CO metabolism with H2production (hydrogenogenic CO metabolism). Indeed, the ability or inability to produce H2with CO oxidation is explained by the presence or absence of this gene cluster inCarboxydothermus hydrogenoformans,Carboxydothermus islandicus, andCarboxydothermus ferrireducens. Interestingly, despite its hydrogenogenic CO metabolism,Carboxydothermus pertinaxlacks the Ni-CO dehydrogenase catalytic subunit (CooS-I) and its transcriptional regulator-encoding genes in this gene cluster, probably due to inversion. Transcriptional analysis inC. pertinaxshowed that the Ni-CO dehydrogenase gene (cooS-II) and distantly encoded energy-converting-hydrogenase-related genes were remarkably upregulated with 100% CO. In addition, when thiosulfate was available as a terminal electron acceptor in 100% CO, the maximum cell density and maximum specific growth rate ofC. pertinaxwere 3.1-fold and 1.5-fold higher, respectively, than when thiosulfate was absent. The amount of H2produced was only 62% of the amount of CO consumed, less than expected according to hydrogenogenic CO oxidation (CO + H2O → CO2+ H2). Accordingly,C. pertinaxwould couple CO oxidation by Ni-CO dehydrogenase II with simultaneous reduction of not only H2O but also thiosulfate when grown in 100% CO.IMPORTANCEAnaerobic hydrogenogenic carboxydotrophs are thought to fill a vital niche by scavenging potentially toxic CO and producing H2as an available energy source for thermophilic microbes. This hydrogenogenic carboxydotrophy relies on a Ni-CO dehydrogenase-energy-converting hydrogenase gene cluster. This feature is thought to be common to these organisms. However, the hydrogenogenic carboxydotrophCarboxydothermus pertinaxlacks the gene for the Ni-CO dehydrogenase catalytic subunit encoded in the gene cluster. Here, we performed a comparative genome analysis of the genusCarboxydothermus, a transcriptional analysis, and a cultivation study in 100% CO to prove the hydrogenogenic CO metabolism. Results revealed thatC. pertinaxcould couple Ni-CO dehydrogenase II alternatively to the distal energy-converting hydrogenase. Furthermore,C. pertinaxrepresents an example of the functioning of Ni-CO dehydrogenase that does not always correspond to its genomic context, owing to the versatility of CO metabolism and the low redox potential of CO.

First-principles insights into ammonia decomposition on MoN (0001) surface

2021 ◽  
Author(s):  
kun yuan ◽  
pengju hao ◽  
Xiaolin Li ◽  
Yang Zhou ◽  
jiangbo zhang ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Surface Energy ◽  
Geometric Structure ◽  
First Principles ◽  
Density Functional ◽  
Slab Model ◽  
Ammonia Adsorption ◽  
Functional Theory ◽  
Dehydrogenation Mechanism

Density functional theory (DFT) and periodic slab model were used to study the geometric structure, electronic structure and dehydrogenation mechanism of ammonia adsorption on MoN (0001) surface. The surface energy...

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