Temperature Carbon Monoxide Oxidation Research Articles

ZnCo2O4 supported low-loading Pd as an enhanced catalyst for low temperature oxidation of carbon monoxide

We have successfully synthesized a series of Pd/ZnCo2O4 supported catalytic materials with low noble metal loading and high activity by the impregnation method. The Pd/ZnCo2O4 catalysts containing 0.2% Pd have superior performance for oxidizing CO at 80 °C, achieving 100% conversion. There is also no loss of activity after four cycles of tests, with the conversion remaining approximately 100%. Aside from that, various advanced physicochemical characterizations indicate that this excellent catalytic performance stems from the interaction between metal Pd and carrier ZnCo2O4. Pd provides a higher degree of accessibility to the active site, while ZnCo2O4 as a carrier can better stabilize Pd nanoparticles. The 0.2% Pd/ZnCo2O4 exhibits higher levels of Pd2+ species as the electronic interaction between Pd and ZnCo2O4 improves, thus improving CO oxidation catalytic efficiency. Furthermore, the low loading of Pd is crucial for reducing the cost of noble metal catalysts and ameliorating their practicality in industrial applications.

Effect of tin content on TiO2-supported platinum-tin bimetallic catalysts for low temperature CO oxidation reaction

Removal of carbon monoxide (CO) is a significant issue in fuel processing for the production of hydrogen. Bimetallic platinum-tin catalysts are well-known as efficient catalysts for oxidation process due to their synergistic bi-functional mechanism, their ability to dissociate molecular oxygen at low temperature, and their capacity to adsorb both atomic oxygen and CO. In this study, we synthesized titanium dioxide supported platinum-tin bimetallic catalysts for low temperature CO oxidation process with different amount of tin. Titanium dioxide provided oxygen to active sites due to its abundant oxygen vacancies and prevented metal sintering of active platinum nanoparticles. We confirmed that our titanium dioxide supported platinum-tin bimetallic catalysts showed excellent performance for low temperature CO oxidation. Moreover, the amount of tin on titanium dioxide affected the adsorption behaviors of CO and O2, resulting in the difference in catalytic activity of Pt based catalysts.

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.

To optimized various parameters of Hopcalite catalysts in the synthetic processes for low temperature CO oxidation

Carbon monoxide (CO) is very poisonous gasses present in the atmosphere and lower temperature complete oxidation of CO is very important processes for all life support. The automobile vehicles exhaust is one of the major sources of CO produced into the environment. The application of catalytic converter in automobile vehicles reduces the toxic gasses emission. There are lots of catalysts used in the catalytic converter for CO oxidation purposes among these catalysts the Hopcalite (CuMnOx) is one of the oldest and best-known catalysts for low temperature CO oxidation. The hopcalite catalyst is prepared by the co-precipitation method and preparation parameters like magnetic shaker shaking speed, shaking time, shaking temperature and pH has an influence on the activity of resultant catalysts. The activity of catalyst was measured in reactive calcinations (RC) conditions at the presence of (1.5% CO) and air. The reaction temperature was increased from room temperature to higher temperature at which the total oxidation of CO was achieved. The characterizations of catalysts are done by several techniques like XRD, FTIR, BET and SEM-EDX. These results are interpreted in terms of structure the active catalyst. The reusability of CuMnOx catalyst was also tested and also found that this catalyst does not show any high level of significant change in its catalytic performances even after reuses.

Synthesis and applications of titanium oxide catalysts for lower temperature CO oxidation

Carbon monoxide (CO) is one of the very poisonous gasses and major sources of CO produced into the environment by the automobile vehicles exhaust. There are various types of catalysts have been used in the catalytic converter for CO oxidation. The titanium dioxide (TiO2) is one of the best transitional metal oxides catalysts for lower temperature CO oxidation. A small amount of TiO2 was deposited on the mesoporous Al2O3 using atomic layer deposition and subsequent oxidation at the different temperatures. The lightly reduced support improves the high catalytic activity of the adparticles, a strongly reduced one quenches the CO oxidation. The quenching is due to thermally activated diffusion of Ti3+ interstitials from the bulk to the surface where they deplete the oxygen adsorbed onto the clusters by the formation of TiOx (x ​≃ ​2) structures. The additions of promoters and support in titanium oxide catalysts improved their performances and reduced their stability. The bulk reduction state of TiO2 strongly affects the catalytic activity of supported metal clusters in the chemical reactions between oxygen and other molecules. The certain attention has been paid on the recovery of TiO2 catalysts from reaction systems and their reuse for various times without losses of catalytic activity in CO oxidation. This investigation will shown scientific basis for potential design of Ti-oxide nano-particle catalysts for lower temperature CO oxidation.

Palladium nanoparticles impregnated activated carbon material for catalytic oxidation of carbon monoxide

Synthesis of nanoparticles by green method is the most attractive alternative in nanoscience and technology as the process is environmentally benign, simple and cost effective. Metal nanoparticles (NPs) supported catalysts are effective for removing toxic gases such as carbon monoxide (CO). Activated carbon-based materials are generally used as support material for NP impregnation. This study investigates the room temperature oxidation of CO over palladium nanoparticles (PdNPs) impregnated on activated carbon fiber cloth (ACFC). For that, PdNPs impregnated activated carbon fiber cloth catalyst is prepared by a green method using ascorbic acid and green tea as reducing agents. The method utilizes spent Pd/C as a precursor for Pd. Atomic absorption spectroscopy (AAS), BET surface area analyzer, Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDS), X-ray powder diffraction (XRD), Temperature programmed reduction (TPR) and X-ray photoelectron spectroscopy techniques were used to characterize the prepared PdNPs impregnated carbon fiber cloth catalysts. The Pd/ACFC catalysts were then tested for its applicability for the oxidative removal of CO, one of the major air pollutants. The efficiency studies were carried out both in the presence and absence of moisture. The metal ions were found to reduce to metal NPs depending on the size of the biomolecules used in the study. As the size of green tea catechins are bigger compared to ascorbic acid and the surface of ACFC is mainly composed of micro pores, the conversion of Pd ions to metallic Pd is not favoured and the catalyst is inefficient for the removal of CO irrespective of the presence and absence of moisture. On the other hand, the surface of ascorbic acid reduced catalyst is composed of both Pd0 and Pd+2 with Pd+2 as the major species. Accordingly, the catalyst shows 100% efficiency for the oxidative removal of CO at 5% moisture over a period of 300 min. It was also observed that high moisture percentage has a retardation effect on the catalyst efficiency, irrespective of the oxidation state of Pd.

Low temperature oxidation of carbon monoxide for heat recuperation: A green approach for energy production and a catalytic review

Low-temperature catalytic oxidation of carbon monoxide to carbon dioxide has been broadly studied in literature in the view of air purification, recovery of hydrogen and reduction of industrial stack emissions. However, neither of the previously studied articles has reported the oxidation of carbon monoxide for capturing the heat generated in the exothermic reaction and simultaneously utilizing the carbon dioxide for producing chemical/petrochemical products. Thus, the current article unprecedentedly occupies an important place in literature that discusses various aspects of low-temperature oxidation of carbon monoxide for heat recuperation. The present work has identified carbon monoxide as a potential heat generator and thereby also unparallely proposed a novel zero carbon emission or NERS process to use carbon monoxide as a fuel in various industries for energy generation. In order to select the best suitable catalyst for mitigating the activation energy barrier associated with oxidation of carbon monoxide, a meticulous selection process is described with chronological and categorical literature review, and thereby concentrating the scattered literature and simultaneously alleviating the complexities involved in the catalyst selection procedure. A techno-economic analysis of the proposed NERS process is also provided with additional discussion on the benefits of carbon credits in order to confer the potential to scale up the process. Thus, the article describes a novel and a cleaner approach for the production of energy in order to take an important step towards sustainable development.

Ambient temperature complete oxidation of carbon monoxide using hopcalite catalysts for fire escape mask applications

Carbon monoxide (CO) is one of the most poisonous gases present in the atmosphere. It also called the silent killer of twenty-first century. CO is produced into the environment by incomplete combustion of carbon containing compounds. It causes lots of people die every year including the firefighters. The main aim of this work to find out the literature study of standard respiratory escape masks for ambient temperature CO oxidation purposes. The research under concern is applicable for developing respiratory protection systems for military, mining, and space devices. There are many catalysts which are active for this process under different conditions. Among these catalysts, the hopcalite (CuMnOx) is one of the best-known catalysts for low-temperature CO oxidation. It is a low-cost, easily available, and highly stable catalyst. The hopcalite catalyst is active for a longer time and would be tolerant of moisture and impurities in reacting gases. The catalyst surface and reacting gases forever play a key role in catalytic reactions. Hopcalite is an ideal catalyst for use in next-generation respiratory protection devices. Although there are numerous research papers present on this topic until now no one review are present for demanding this issue. So there is a space in this area; it has been made an attempt to seal this hole by this review.

Synthesis of silver promoted CuMnOx catalyst for ambient temperature oxidation of carbon monoxide

Abstract The present research shows that the addition of silver (Ag), by the deposition-precipitation method, to a mixed CuMnOx catalyst can improve the activity of carbon monoxide (CO) oxidation. The CuMnOx catalyst doped with 3 wt.% Ag shows a higher catalytic activity as compared to the 1, 2, 4 and 5 wt.% Ag doped samples. The loading of Ag could introduce new active sites into the CuMnOx catalyst and reduce its deactivation. The order of the optimal calcination strategies based on the performance of catalysts for CO oxidation is as follows: Reactive Calcination > Flowing air > Stagnant air. All the catalysts were characterized by XRD, FTIR, BET, XPS and SEM-EDX techniques. It was found that the high active surface area was one of the main factors for the high catalytic activity of the Ag-promoted CuMnOx catalyst.

Preparation and Characterization of UiO-66-Supported Cu–Ce Bimetal Catalysts for Low-Temperature CO Oxidation

A series of Zr-based metal–organic frameworks (UiO-66) supported CuO–CeO2 catalysts with various total metal loadings and various Cu/Ce ratios were prepared by using a co-impregnation method. The catalytic activities of the catalysts for low temperature oxidation of carbon monoxide were compared with that supported on the ZrO2 and mesostructured cellular foam silica. The results show that the catalysts supported by UiO-66 are expected to give the best catalytic activity, which should be attributed to the special construction of UiO-66. The samples were further characterized by XRD, TEM, N2 adsorption–desorption, H2-TPR, XPS, and in situ DRIFT. And the catalyst with a bimetallic loading of 50 wt% and Cu/Ce ratio of 3:7 (wt/wt) has the highest catalytic activity, which can be attributed to the larger amount of finely dispersed Cu species strongly interacting with CeO2, the highest amounts of oxygen vacancies and Cu+ species on the catalyst surface.

CeO2 supported low-loading Au as an enhanced catalyst for low temperature oxidation of carbon monoxide

A series of low loading and high activity Au/CeO2 supported catalysts were synthesized using a coprecipitation method. Au/CeO2 catalysts with a low Au content (0.2 wt%) showed extremely high activity for CO oxidation with 100% conversion of CO around 60 °C.

Aluminum cluster for CO and O2 adsorption.

Low temperature oxidation of CO to CO2 is an important process for the environment. Similarly adsorption of CO from the releasing sources is also of major concern today. Whereas the potential of gold and silver clusters is well proven for thecatalysis of the above mentioned reaction, the potential of aluminum (Al) clusters remains unexplored. The present study proves that, similar to the transition metals, Al clusters can also be used for adsorption of gases. We first tested the potential of Al cluster as adsorbents for CO. The high binding energy (BE) values prove that Al clusters can be used for adsorbing both CO and O2. Since oxygen binding is more facile, we adsorbed oxygen on Al and then checked the effect of this O2 on the BE of CO. The results were obtained by DFT calculations at M062X/TZVP level of theory. Graphical abstract Activation of carbon monoxide (CO) on oxygen-adsorbed aluminum (Al) cluster.

Nickel Nanocatalyst Ex-Solution from Ceria-Nickel Oxide Solid Solution for Low Temperature CO Oxidation.

In this work, in situ growth of Ni nanocatalysts to attach onto the ceria (CeO2) surface through direct Ni ex-solution from the NiO-CeO2 solid solution in a reducing atmosphere at high temperatures with an aim to improve the catalytic activity, and stability for low temperature carbon monoxide (CO) oxidation reaction have been reported. The NiO-CeO2 solid solutions were prepared by solution combustion method, and the results of XRD and RAMAN showed that doping of Ni increases the oxygen vacancies due to charge compensation. Ni is clearly visible in XRD and TEM of Ni ex-solved sample (R-UCe5Ni10) after reduction of NiO-CeO2 (UCe5Ni10) sample by 5% H2/Ar reduction at 1000 °C. TEM analysis revealed a size of 9.2 nm of Ni nanoparticle that is ex-solved on the surface CeO2. This ex-solved sample showed very high catalytic activity (T50 ~ 110 °C), and stability (100 h) for CO oxidation reaction as compared to prepared solid solution samples. This is due to the highly active metallic nano-phase which is ex-solved on the surface of CeO2 and strongly adherent to the support. The apparent activation energy Ni ex-solved sample is found out to be 48.4 kJ mol-1. Thus, the above Ni ex-solved sample shows a practical applicability for the CO reaction.

Effect of various metal oxides phases present in CuMnOx catalyst for selective CO oxidation

Hopcalite (CuMnOx) is a highly efficient catalyst for low temperature oxidation of Carbon monoxide (CO). As synthesized by Co-precipitation method, it shows the high activity for CO oxidation. The coordination between CuO and MnOx in CuMnOx catalyst improves the catalytic activity for CO oxidation. In this research work, we investigate the individual catalytic activity of CuO and MnOx and compare with the multiphase CuMnOx catalyst. The performance of multiphase catalysts CuO and MnO2 were numerous times higher as compared to single phase CuMnOx. The activity order of catalysts for CO oxidation was as follows: CuMnOx> MnOx > CuOx. The success of CuMnOx catalyst has prompted a great deal of research work into each component and nature of active sites. In CuMnOx catalyst, the MnOx acts as an oxygen donor and CuO acts as an oxygen acceptor. The presence of MnOx is possible to assist in the reduction of CuO, due to the coordination between CuO and MnOx. The calcination strategies of precursors highly affect the physicochemical and catalytic properties of the catalysts for CO oxidation. The reactive calcination (RC) conditions (4.5% CO in air) for prepared catalysts showed the best activity result for CO oxidation, as compared to the traditional method of calcination.

A highly moisture-resistant binary M3Co16Ox composite oxide catalysts wrapped by polymer nanofilm for effective low temperature CO oxidation

A series of M3Co16Ox (M = Cr, Ti, Zr, Fe, Mn) oxide catalysts wrapped by polymer nanofilm were developed by the solid-phase method, and the catalytic activities were investigated for low temperature oxidation of carbon monoxide under moisture-rich condition. The catalysts were characterized by HR-TEM, FT-IR, XRD, N2 adsorption-desorption, H2-TPR, CO-TPD and XPS techniques. The results reveal that the M3Co16Ox composite oxides are high-dispersive mesoporous materials coated by polymer nanofilm with an average thickness in the scope of 4–7 nm. The percentages of surface oxygen vacancy and lattice oxygen on the catalysts decrease in the following order: Mn3Co16Ox > Fe3Co16Ox > Zr3Co16Ox > Ti3Co16Ox > Cr3Co16Ox, which is consistent with their catalytic performances. Among all the prepared catalysts, the polymer nanofilm wrapped Mn3Co16Ox nanoparticles possess the highest Co3+/Co2+ ratio (1.56), the highest percentage of surface oxygen vacancy (17.5%) and lattice oxygen (62.2%), resulting in the best catalytic activity, such as, 100% conversion at 55 °C under moisture-rich condition (∼0.6 vol.%). Moreover, the Mn3Co16Ox catalyst also exhibits long-term catalytic stability (>one month) even at a very high water vapor level (3.1 vol.%) and considerably low temperature (85 °C).

High catalytic activity of Pt–Pd containing USY zeolite catalyst for low temperature CO oxidation from industrial off gases

Small amounts (0.15wt%) of platinum and palladium were incorporated in porous, high surface area, ultra–stable H–USY–Zeolite by ion exchange method, and their catalytic activity was studied for carbon monoxide (CO) oxidation reaction, under various conditions of industrial importance. The catalyst was characterized by p–XRD, chemical analysis, SEM, TEM, evaluated for catalytic activity using a steady state, fixed bed catalytic reactor. The catalysts show high CO oxidation activity and it was possible to convert 0.044 mmols of CO per gram of catalyst at 120 °C, at a space velocity of 60 000 h−1 and with 100 ppm CO concentration in feed gas. The high catalytic activity of this noble metal catalyst also appears to be a factor of porous structure of zeolite facilitating mass transfer; high surface area as well as highly dispersed catalyst sites of palladium and platinum on zeolite structure. Introduction of acidic sites in zeolites probably makes them more resistant towards SO2, while their surface area and pore characteristics make this catalyst efficient even under high space velocity conditions, thus suggesting the potential of larger pore size zeolites over conventional porous materials for industrial applications.

Mechanochemical synthesis of copper manganese oxide for the ambient temperature oxidation of carbon monoxide

A series of copper manganese oxide catalysts have been prepared by mechanochemical grinding of carbonate precursors and tested for the low temperature oxidation of CO. It is shown that a 72h grind time and heat treatment under oxygen is necessary to form active CuMn2O4 for the conversion of CO to CO2 at room temperature. Energy dispersive X-ray analysis mapping indicated that the degree of mixing was improved at longer grinding times. Contraction of the MnCO3 lattice, followed by X-ray diffraction, showed that grinding times in excess of 24h were necessary for the near complete dissolution of Cu ions into the MnCO3 framework, which in turn facilitated the formation of CuMn2O4 upon calcination. This simple, clean and environmentally friendly synthesis shows how mixed metal oxides that are catalytically active at room temperature can be synthesized without employing aqueous precipitation techniques, which result in waste streams containing carbonate and nitrate contaminants.

Catalytic performance of Ag/Fe2O3 for the low temperature oxidation of carbon monoxide

In this paper, the effect of impregnated Ag nanoparticles into Fe2O3 support in catalytic low temperature CO oxidation was investigated. The nanocatalysts were prepared with a conventional impregnation method. The prepared samples were characterized by X-ray diffraction (XRD), N2 adsorption/desorption, Temperature programmed reduction (TPR) and Transmission electron microscopy (TEM) techniques. It is clearly observed from the TEM images that the Ag nanoparticles are highly dispersed on the surface of Fe2O3 and are mostly around 5nm in size. The results reveal that the catalytic activities increased significantly by increasing the Ag content, which causes a strong interaction with the Fe2O3. The catalytic activity clearly correlates with the Ag–Fe2O3 interaction. The experiments showed that the Fe2O3 supported silver catalyst has a good reproducibility and is highly stable for CO oxidation for a 50h period of time even in the presence of high amount of moisture and CO2 in the feed gas.

Nanotechnology for Pollution Reduction

Abstract Nanotechnology is regarded as the next great scientific/industrial revolution due to the possibility of designing nanostructured materials that possess novel electronic, optical, magnetic, and catalytic properties. Nanomaterials could potentially be applied in pollution control, catalysis, water remediation, clean energy. Nanocatalysis is a phenomenon of significant research and important practical applications in a variety of fields such as materials, environmental and atmospheric sciences. Low-temperature catalytic oxidation of carbon monoxide (CO) is one of the most important problems in pollution since even small exposures to CO (ppm) can be lethal. Nanophase metal and metal oxide catalysts, with controlled particle size, high surface area, and more densely populated unsaturated surface coordination sites, could potentially provide significantly improved catalytic performance over conventional catalysts. It is therefore, expected that nanoparticle catalysts would show high catalytic activity for the low temperature oxidation of CO than bulk materials. Noble metals are well known oxidation catalysts with high activity and stability, even in the presence of moisture and sulfur compounds, and they are usually used in gas exhaust emissions control. The high cost of precious metals and their sensitivity to sulfur poisoning motivated re-searchers to search for new catalysts. Alloying is a phenomenon that can either improve the catalytic properties of the original single-metal catalysts for CO oxidation. Recently, we reported the effect of support on the catatalytic activity of Au catalyst. We have prepared metallic and bimetallic nanocatalysts on different supports using differ-ent synthesis methods. The catalytic activity of each catalyst was carried out by using a flow tube reactor coupled to an infrared detector. Our results indicate that unsupported AuCu alloy shows higher activity than Au or Cu alone. These results attributed to the formation of CuO within the bimetallic nanoparticles, which improves the catalytic activity of Au-Cu alloy nanoparticle. On the other hand, Au nanoparticles supported on CeO2 exhibit higher catalytic activity than Cu, CuO, and AuCu alloy supported on CeO2. These results attributed to the strong interaction of Au with CeO2.

Base Metal Oxides Active for Low Temperature CO Oxidation

Among base metal oxides, Co3O4, MnO2, and NiO, which have p-type semiconducting properties, hold potential catalytic capability for the oxidation of carbon monoxide (CO) at temperatures below 0oC. Either of the following requirements should be fulfilled; low moisture content in reaction feed, optimum temperature and atmosphere for catalyst pretreatments, and the control of metal oxide morphology. Surface oxygen vacancies are assumed to play a key role in low temperature CO oxidation.