Catalytic Conversion Of Carbon Monoxide Research Articles

A DFT Study of CO Hydrogenation on Graphene Oxide: Effects of Adding Mn on Fischer–Tropsch Synthesis

The hydrogenation of carbon monoxide (CO) offers a promising avenue for reducing air pollution and promoting a cleaner environment. Moreover, by using suitable catalysts, CO can be transformed into valuable hydrocarbons. In this study, we elucidate the mechanistic aspects of the catalytic conversion of CO to hydrocarbons on the surface of manganese-doped graphene oxide (Mn-doped GO), where the GO surface includes one OH group next to one Mn adatom. To gain insight into this process, we have employed calculations based on the density functional theory (DFT) to explore both the thermodynamic properties and reaction energy barriers. The Mn adatoms were found to significantly activate the catalyst surface by providing stronger adsorption geometries. Our study concentrated on two mechanisms for CO hydrogenation, resulting in either CH4 production via the reaction sequence CO → HCO → CH2O → CH2OH → CH2 → CH3 → CH4 or CH3OH formation through the CO → HCO → CH2O → CH2OH → CH3OH pathway. The results reveal that both products are likely to be formed on the Mn-doped GO surface on both thermodynamic grounds and considering the reaction energy barriers. Furthermore, the activation energies associated with each stage of the synthesis show that the conversion reactions of CH2 + OH → CH3 + O and CH2O + OH → CH2OH + O with energy barriers of 0.36 and 3.86 eV are the fastest and slowest reactions, respectively. The results also indicate that the reactions: CH2OH + OH → CH2 + O + H2O and CH2OH + OH → CH3OH + O are the most exothermic and endothermic reactions with reaction energies of −0.18 and 1.21 eV, respectively, in the catalytic pathways.

Catalytic conversion of carbon monoxide on mono and bi modified with cobalt and copper VPO systems

Catalytic conversion of carbon monoxide on mono and bi modified with cobalt and copper VPO systems

Influence the performances of hopcalite catalysts by the addition of gold nanoparticle for low temperature CO oxidation

The catalytic conversion of carbon monoxide (CO) into carbon dioxide (CO 2 ) at a low temperature is very important procedure for all living beings present in the environment. The present study represents that the addition of gold (Au) nano-particles, by the deposition-precipitation method into the hopcalite (CuMnOx) catalyst has been improving their performances for CO oxidation. The CuMnOx catalyst loading by 0.75 wt% Au was representing that the best catalytic activity for CO oxidation than the other catalysts loading by 0.25, 0.5 and 1 wt% Au. The small amount of Au doping (0.75 wt%) in CuMnOx catalyst improves their performances for CO oxidation at an ambient conditions. The gold nano-particles will be introducing the new active sites into the CuMnOx catalyst surfaces and decreases the deactivation of catalyst. The lattice oxygen movement was a major important factor which can influences the performances of hopcalite catalyst for CO oxidation. The calcinations strategies (reactive calcinations and traditional calcinations) of the precursor have huge impacts on the performances of resulting catalysts. The reusability of Au promoted CuMnOx catalyst was also measured and found that this catalyst does not have any major changes in its catalytic performances still after the reuses.

Small-Scaled Production of Blue Hydrogen with Reduced Carbon Footprint

This article reviews a method of hydrogen production based on partial non-catalytic oxidation of natural gas in an original synthesis gas generator. The working principles of the unit are similar to those of liquid-propellant rocket engines. This paper presents a description of the operation and technical characteristics of the synthesis gas generator. Its application in the creation of small-scaled plants with a capacity of up to 5–7 thousand m3/h of hydrogen is justified. Hydrogen production in the developed installation requires a two-stage method and includes a technological unit for producing a hydrogen-containing gas. Typical balance compositions of hydrogen-containing gas at the synthesis gas generator’s outlet are given. To increase the hydrogen concentration, it is proposed to carry out a two-stage steam catalytic conversion of carbon monoxide contained in the hydrogen-containing gas at the synthesis gas generator’s outlet using a single Cu–Zn–cement-containing composition. Based on thermodynamic calculations, quasi-optimal modes of natural gas partial oxidation with oxygen are formulated and the results of material balance calculation for the installation are presented. In order to produce “blue” hydrogen, the scheme of carbon dioxide separation and liquefaction is developed. The conclusion section of the paper contains the test results of a pilot demonstration unit and the recommendations for improving the technology and preventing soot formation.

FORMATION OF IMPURITIES IN SYNTHESIS GAS AT STAGE OF CONVERSION OF CARBON MONOXIDE TO HYDROGEN IN AMMONIA PRODUCTION

The article analyzes the work of the department for the conversion of carbon monoxide with water vapor to hydrogen as part of the ammonia synthesis unit. The effect of temperature and duration of operation of the medium-temperature conversion catalyst on the technical and technological parameters of the process is shown. The catalytic conversion of carbon monoxide is an important component of the hydrogen production process in the industrial technology of deep processing of natural gas. In modern ammonia synthesis units, the conversion process takes place in two stages: first, at a temperature of 360 – 430 °C on iron-chromium, and then at 190 – 260 °C on a copper-containing catalyst. It was found that along with the main products (H2, CO2), the presence of undesirable impurities of ammonia, amines, alcohols, acetates and formates was detected in the synthesis gas. It is shown that the main by-product at the stage of medium-temperature conversion is ammonia, the content of which in the condensate reaches 80-85%. Methanol is formed as a by-product both at the stage of medium-temperature (9-13%) and low-temperature conversion (87-91%). Most of the methanol generated during the conversion process is condensed with water in separators, while the rest goes to the CO2 removal system. In the separator, where the temperature is 160-162 °C, on average 68% of methanol remains in the gas phase, and in the separator, where deeper gas cooling is applied to 72 °C, about 81% of methanol remains in the condensate. To decrease the methanol content, it is necessary to lower the conversion temperature and increase the gas space velocity. Under the conditions of ammonia production from methanol and ammonia, a mixture of amines of varying degrees of substitution is formed, predominantly methylamine (CH3)NH2 and demytylamine (CH3)2NH2. Moreover, about 35-40% of the formed amines goes into condensate, and most of it remains in the gas phase and goes to the stage of cleaning from CO2. In the production of ammonia, solutions based on potash - K2CO3 are used to clean the converted gas from CO2, which absorb organic impurities, which are formed mainly at the stage of low-temperature conversion. Impurities impair the operation of the purification stage and cause foaming of solutions. One of the reasons for foaming is the presence of organic matter degradation products in the solution.

Synthesis of Hopcalite catalysts by various methods for improved catalytic conversion of carbon monoxide

The conversion of carbon monoxide (CO) at ambient condition is major procedure for human life protection. The Hopcalite (CuMnOx) is one of the best known catalysts for lower temperature CO conversion. The synthesis of hopcalite catalysts by various methods including Co-precipitation (CP), Sol-gel (SG), Reactive grinding (RG), Impregnation (I) and Pyrolysis (P) highly effects on the performance of final catalysts for CO conversion. In this experimental work various types of hopcalite catalysts prepared by various methods (CP, SG, RG, I, and P) followed by calcination in reactive (CO-air) mixture and traditional calcination conditions. The performance of different hopcalite catalysts for CO conversion reaction was as follows: CuMnCP > CuMnRG > CuMnSG > CuMnP > CuMnI. The Co-precipitation method synthesized hopcalite catalyst followed by reactive calcination conditions represents that the most excellent catalytic performance for complete conversion of CO at 80 °C. The order of synthetic conditions based on the activity of hopcalite catalysts matched with their characterization. Our effort to demonstrates that the simplistic and potential strategy for improvement of catalytic perfromances over hopcalite catalysts, which should be suitable for different chemical reactions. Hopcalite is a lower cost, simply aviliable and recycle catalysts for application in catalytic converter for CO conversion purposes.

Mesoporous MFI Zeolite Nanosponge Supporting Cobalt Nanoparticles as a Fischer–Tropsch Catalyst with High Yield of Branched Hydrocarbons in the Gasoline Range

A zeolite nanosponge was obtained by a seed-assisted hydrothermal synthesis route using C22H45–N+(CH3)2–C6H12–N+(CH3)2–C6H13 as the structure-directing agent. The zeolite was composed of disordered network of 2.5-nm-thick MFI zeolite nanolayers having a narrow distribution of mesopore diameters centered at 4 nm. The highly mesoporous texture (mesopore volume = 0.5 cm3 g–1) was suitable for supporting cobalt nanoparticles with a narrow distribution of particle diameters centered at 4 nm. The Co/MFI zeolite exhibited high stability of the Co nanoparticles against particle growth, and there was accordingly high catalytic conversion of carbon monoxide to hydrocarbons and long catalytic lifetime in the Fischer–Tropsch synthesis. Furthermore, the Co/MFI catalyst exhibited high selectivity for branched hydrocarbons in the gasoline range (C5–C11), compared to conventional alumina-based catalysts. This high selectivity could be attributed to hydroisomerization in the extremely thin zeolite frameworks that provided...

Production of hydrogen-containing gas using the process of steam-plasma gasification of used tires

The paper is devoted to treatment of used tires. The method of used tire gasification using steam plasma has been suggested. Studies of the composition of syngas depending on the process temperature and the steam-plasma flow rate have been performed. The method for increasing the hydrogen content in synthetic gas using the steam catalytic conversion of carbon monoxide contained in syngas in the presence of an absorber has been suggested. The results of the process mathematical simulation at different consumptions of steam and absorber are presented.

? Nonthermal Plasma-enhanced Catalytic Methanation of CO over Ru/TiO2/Al2O3

Catalytic methanation of carbon monoxide (CO) was investigated in a nonthermal plasma (NTP) reactor packed with Ru/TiO2/Al2O3 catalyst pellets. With the NTP alone, no conversion of CO was observed over the entire temperature range of 240 300 ◦C, but the combination of plasma and catalyst was found to greatly improve the catalytic conversion of CO, particularly in the lower temperature region below 280 ◦C. Higher CO conversion efficiencies were obtained at higher applied voltages because of increased NTP action in the catalytic reactions. The increase in the voltage resulted in a decrease in the activation energy for methanation. Reaction products, including CH4 and CO2, were identified by using a Fourier transform infrared (FTIR) spectrometer. The increases in the applied voltage and in the temperature tended to slightly bring down the selectivity toward CH4, it being more than 0.93 under all experimental conditions explored.

Gold supported iron oxide–hydroxide derived from iron ore tailings for CO oxidation

Iron ore tailing, a waste material of iron ore industry, has been used to prepare iron oxide–hydroxide support for anchoring nano-gold particles. FeOOH was prepared from iron chloride solution obtained from acid digestion of iron ore tailing. Precipitation deposition method was used to prepare Au supported FeOOH. The samples were characterized by XRD, TEM, TG-DTA and FTIR. The XRD studies have confirmed the FeOOH phase and the TEM studies reveal the anchoring of gold particles on FeOOH whose size is about 5 nm. FTIR spectra showed the vibration mode of metal–oxygen bond and the presence of hydroxyl group in FeOOH and Au/FeOOH. TG-DTA results confirmed dehydration of FeOOH and the process is retarded by the presence of Au particles. The catalytic conversion of carbon monoxide by Au/FeOOH was around 55% but the catalyst became inactive after pretreatment at 300 °C in presence of oxygen which led to agglomeration of Au particles and removal of hydroxyl groups from the surface of FeOOH.

Rare earth hydroxycarbonate materials with hierarchical structures: Preparation and characterization, and catalytic activity of derived oxides

A hydrothermal process is reported for the preparation of rare earth hydroxycarbonates LnOHCO 3 (Ln = Pr, Sm, Dy, Y) with hierarchical structures, such as dumbbell nanorod clusters, stacked lamellae and patched rods. All the hydroxycarbonate samples show fluorescence, and the emission wavelengths and intensity may be different for different samples. The hydroxycarbonate samples are generally stable under 380 °C, but will decompose to the respective oxides at higher temperatures. The oxides are tested for catalytic conversion of carbon monoxide to carbon dioxide. It reveals that all the rare earth oxides are active to the catalytic reaction, and Sm 2O 3 shows superior catalytic performance to the other oxides.

Crystallography and porosity effects of CO conversion on mesoporous CeO 2

Catalytic properties and thermal stability were studied for samples of mesoporous ceria with different BET specific surface area. The catalytic conversion of carbon monoxide to carbon dioxide and how thermal treatments of the catalysts influence the catalytic properties have been investigated. The materials were studied by transmission electron microscopy and by conversion profile measurements of CO versus temperature using a plug flow micro reactor made in quartz glass only. In order to compare the catalytic properties associated with a specific structure or morphology directly, aliquots of surface area (0.6 m 2) of the catalyst was used. Scanning electron microscopy and X-ray energy-dispersive spectrometry (XEDS) were used for surface morphology studies and elemental analysis. It was found that the proportion of {1 0 0} surfaces determine the catalytic properties of the material and these surfaces become important at calcination temperatures between 773 and 973 K. The internal mesoporous structure is destroyed at calcination temperatures around 873 K.

97/00298 Method and apparatus for catalytic conversion of carbon monoxide to carbon dioxide and hydrogen

97/00298 Method and apparatus for catalytic conversion of carbon monoxide to carbon dioxide and hydrogen

Promoter action of rare earth oxides in rhodium/silica catalysts for the conversion of syngas to ethanol

The promoter action of rare earth oxides (REO) (La 2O 3, CeO 2, Pr 6O 11, Nd 2O 3, and Sm 2O 3) in Rh/SiO 2 catalysts for syngas conversion to ethanol and the characterization of these catalysts by X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) have been investigated. The addition of REO, especially CeO 2 and Pr 6O 11, increases markedly the selectivity for production of ethanol. High-temperature reduction of the catalyst favours selectivity for ethanol in all REO promoted rhodium catalysts. XPS measurements revealed that CeO 2 in Rh-CeO 2/SiO 2 mostly exists as Ce 2O 3 after reduction, in contrast to that in rhodium-free CeO 2/SiO 2. It is concluded that rhodium assists in the reduction of CeO 2. Correlation was found between the selectivity for ethanol and the reducibility of REO. The surface mean diameters of rhodium particles in Rh-REO/SiO 2, as observed by TEM, lie in the range 4 to 6 nm and do not change after high-temperature reduction. The nature of rhodium-promoter interactions and a synergistic mechanism of rhodium coupled with REO for catalytic conversion of carbon monoxide are discussed.

Catalytic Conversion of Carbon Monoxide and Carbon Dioxide into Methanol with Photocells

It has been shown that and can be selectively converted to methanol at ambient temperature. This is based on the redox reaction being composed of the reduction of or into methanol and the oxidation of Everitt's salt (ES,) to Prussian blue (PB, ). The reaction can only be activated by homogeneous catalysts consisting of a metal complex and a primary alcohol. ES is required to be regenerated using an external electric energy in order to obtain the continuous conversion of and . The sources of such required energy were an electrochemical photocell and a solar cell. Reduction mechanisms are discussed based on the results from IR and 13C‐NMR spectra.

Catalysts for Fischer-Tropsch and Isosynthesis

A review relates the products from various catalytic systems including promoters, that may be useful in the catalytic conversion of carbon monoxide derived from coal into methane, higher hydrocarbons, alcohols, or other oxygenated species, with specific emphasis on Fischer--Tropsch synthesis and isosynthesis (to saturated branched hydrocarbons); discusses the effectiveness of iron, nickel, cobalt, and ruthenium catalysts for the Fischer-Tropsch synthesis; and evaluates some useful catalysts, e.g., potassium oxide-promoted thoria, for isosynthesis.