Catalysts For Oxidation Of Carbon Monoxide Research Articles

Facile One-step Solvothermal Synthesis of Co3O4/CuO Nanoflowers as An Excellent Catalyst for CO Oxidation in Coal Mines

In the present study, Cobalt oxide (Co3O4)/Copper oxide (CuO) nanoflower catalysts were synthesized through a one-step solvothermal method, and the impact of various factors, including reaction time, on the catalytic activity of the catalysts towards carbon monoxide (CO) was investigated. The results showed that the catalysts synthesized at 140 °C and a reaction time of 4h provided the best catalytic performance for carbon monoxide, and the regular nanoflower-like morphology provided a larger specific surface area as well as a greater number of active sites, allowing the instantaneous 100% elimination of CO at 200 °C. Additionally, a plausible reaction mechanism was elucidated, wherein CO initially adsorbed onto the sample's surface, subsequently reacting with lattice oxygen to form intermediate carbonate species. This process ultimately led to the production of carbon dioxide (CO2), followed by the desorption of CO2 molecules from the sample's surface. The results demonstrate that these composite catalysts effectively mitigate CO levels during CO over limit in coal mines, thereby enhancing the safety of production personnel.

Hybrid Amyloid-Chitin Nanofibrils for Magnetic and Catalytic Aerogels.

In the quest for a sustainable and circular economy, it is essential to explore environmentally friendly alternatives to traditional petroleum-based materials. A promising pathway toward this goal lies in the leveraging of biopolymers derived from food waste, such as proteins and polysaccharides, to develop advanced sustainable materials. Here, we design versatile hybrid materials by hybridizing amyloid nanofibrils derived by self-assembly of whey, a dairy byproduct, with chitin nanofibrils exfoliated from the two distinct allomorphs of α-chitin and β-chitin, extracted from seafood waste. Various hydrogels and aerogels were developed via the hybridization and reassembly of these biopolymeric nanobuilding blocks, and they were further magnetized upon biomineralization with iron nanoparticles. The pH-phase diagram highlights the significant role of electrostatic interactions in gel formation, between positively charged amyloid fibrils and negatively charged chitin nanofibrils. Hybrid magnetic aerogels exhibit a ferromagnetic response characterized by a low coercivity (<50 Oe) and a high specific magnetization (>40 emu/g) at all temperatures, making them particularly suitable for superparamagnetic applications. Additionally, these aerogels exhibit a distinct magnetic transition, featuring a higher blocking temperature (200 K) compared to previously reported similar nanoparticles (160 K), indicating enhanced magnetic stability at elevated temperatures. Finally, we demonstrate the practical application of these hybrid magnetic materials as catalysts for carbon monoxide oxidation, showcasing their potential in environmental pollution control and highlighting their versatility as catalyst supports.

Production of Block Catalysts for Carbon Monoxide Oxidation Using Additive Technologies

Production of Block Catalysts for Carbon Monoxide Oxidation Using Additive Technologies

CO oxidation over three-dimensional transition metal-doped CeO2 catalysts: A density functional calculation study

Carbon monoxide (CO) oxidation is considered one of the effective methods to address environmental pollution caused by vehicle emissions and incomplete combustion of fuels. However, designing efficient and affordable catalysts has always been a major challenge. In this study, a series of transition metals (TMs)-doped CeO2(111) catalysts were designed based on density functional theory (DFT) to catalyze the oxidation reaction of CO. According to the results, TMs-CeO2(111) catalysts exhibited excellent thermal stability and adsorption performance. In particular, Fe-CeO2(111) and Ni-CeO2(111) catalysts displayed good catalytic activity, with their respective rate-determining step energy barriers being 0.57 and 0.43 eV. Of particular note, Fe-CeO2(111) demonstrated high reaction rates at low to medium temperatures, making it a promising candidate for CO oxidation reaction catalyst. This study provides new insights into designing efficient, low-cost, and readily accessible CO oxidation catalysts, and establishes a solid foundation for the development of catalytic combustion kinetic models.

CATALYST BASED ON PALLADIUM(II), COPPER(II) COMPOUNDS AND THERMALLY-MODIFIED TRIPOLI FOR THE PREPARATION OF RESPIRATORY REMEDIES FROM CARBON MONOXIDE IN EMERGENCY SITUATIONS

Nowadays, the number of emergency situations related to fires is quite high. The high percentage of human deaths is mainly due to poisoning by gaseous toxic substances including carbon monoxide. The most problematic issue is the development or application of existing catalysts in means of individual protection of human respiratory organs – respirators, gas masks, self-rescuers. The compositions based on thermally modified tripoli obtained by the method of impregnation of the carrier by moisture content with compounds of copper(II), palladium(II) and potassium bromide were investigated. According to X-ray phase analysis, it was established that thermally modified tripoli is a polyphase crystalline mineral containing the following main phases: a-quartz, a-tridymite, b-cristobalite, a-cristobalite. The influence of the initial concentration of CO, which does not exceed 15 MPC, on the kinetic and stoichiometric parameters of the reaction varied in the range from 100 to 300 mg/m3. It was noted that the reaction rate in the stationary mode (Wst) is directly proportional to the increase in the initial concentration of carbon monoxide in the gas phase. The values of the constant kI and the degree of CO conversion (ηst) do not depend on CinCO, which also confirms the first order of CO concentration. Particular attention is paid to the aspects of ensuring protection against carbon monoxide when its concentration exceeds 15 MPC. Usually, special equipment, such as filtering self-rescuers, is used to clean the air from carbon monoxide at concentrations from 1000 to 6500 mg/m3. The catalyst developed by us is intended for use in lightweight personal respiratory protective equipment (RPE) at concentrations not exceeding 15 MPC. Therefore, there was an interest in researching the possibilities of using this catalyst in the self-saving filter system. The concentration of carbon monoxide in the gas-air mixture was varied from 400 to 2500 mg/m3 in the presence of the К2PdCl4-Cu(NO3)2-КBr/300-Tr(K) system. It was established that Wst increases in direct proportion with an increase in the gas-air mixture up to 1250 mg/m3, which indicates the first order of the reaction according to carbon monoxide. It was found that at CinCO = 1000 mg/m3 only under the condition τ´ = 1.13 s (mk = 10 g) the К2PdCl4-Cu(NO3)2-KBr/Tr catalyst provides air purification below the breakthrough CO concentration (CfCO = 200 mg/m3). Experiments on the influence of SO2 on the activity of carbon monoxide oxidation catalysts have shown that they lose their activity, so in air purification systems from CO, it is necessary to provide for the stage of capturing sulfur dioxide.

Heterogeneous Co1/P1Mo12O40 single-atom catalyst for CO oxidation via termolecular Eley-Rideal (TER) mechanism

Catalytic mechanisms, micro-kinetic and thermodynamics studies of Phosphomolybdic acid (PMA) supported non-noble metal (NNM1 = Sc1, Ti1, V1, Cr1, Mn1, Fe1, Co1, Ni1, Cu1, and Zn1) single-atom catalysts (SACs) are explored for carbon monoxide (CO) oxidation by using DFT calculations. The results reveal that Co1/P1Mo12O40 have demonstrated excellent ability to adsorb (CO, O2) molecules, resulting in significant charge transfer from the catalyst surface to the adsorbate, which is essential to produce CO2 under normal reaction conditions. The various reaction pathways, including Eley Rideal (ER), Langmuir Hinshelwood (LH), Termolecular Eley Rideal (TER), and Mars Van Krevelen (MvK) are explored for CO oxidation on Co1/P1Mo12O40 to authenticate the most auspicious reaction mechanism. The energy barrier for the TER mechanism was 0.41 eV, lower as compared to the other reported materials which suggests that the Co1/P1Mo12O40 SACs would be the most appropriate future material for CO oxidation. To further validate the results, we performed the microkinetic investigation which predicts the CO oxidation rate of 4.58 × 106 s − 1. The key role of spin-magnetic moment for the promotion of CO oxidation by using Co1 single-atom catalyst was revealed from the deep electronic analysis. The current results would provide appreciated guidelines for experimentalists to develop less expensive and more effective non-noble metal SACs for CO oxidation.

Nb2S2C Monolayers with Transition Metal Atoms Embedded at the S Vacancy Are Promising Single-Atom Catalysts for CO Oxidation.

Single atoms anchored on stable and robust two-dimensional (2D) materials are attractive catalysts for carbon monoxide (CO) oxidation. Here, 3d (Fe-Zn), 4d (Ru-Cd), and 5d (Os-Hg) transition metal-decorated Nb2S2C monolayers were systematically studied as potential single-atom catalysts for low-temperature CO oxidation reactions by performing first-principles calculations. Sulfur vacancies are essential for stabilizing the transition metals anchored on the surface of defective Nb2S2C. After estimating the structure stability, the aggregation trend of the embedded metal atoms, and adsorption strength of reactants and products, Zn-decorated defective Nb2S2C is predicted to be a promising catalyst to facilitate CO oxidation through the Langmuir-Hinshelwood (LH) mechanism with an energy barrier of only 0.25 eV. Our investigation indicates that defective carbosulfides can be promising substrates to generate efficient and low-cost single-atom catalysts for low-temperature CO oxidation.

Synthesis and Properties of a Carbon Monoxide Oxidation Catalyst Based on Titanium Dioxide and Platinum Nanoparticles

Synthesis and Properties of a Carbon Monoxide Oxidation Catalyst Based on Titanium Dioxide and Platinum Nanoparticles

Synthesis and Properties of a Carbon Monoxide Oxidation Catalyst Based on Titanium Dioxide and Platinum Nanoparticles

Carbon monoxide oxidation catalysts comprising Pt clusters on titanium dioxide with an oxide particle size of 6 and 20 nm have been synthesized. The catalysts have been studied using TEM, XRD, and XPS techniques, and it has been found that platinum clusters coated with a mixture of platinum oxides are formed on the support surface. The coherent scattering region of the Pt cluster is close to 5–6 nm for the studied oxide supports. The catalytic properties in the CO oxidation reaction at 295 K and low CO concentrations(less than 100 mg/m3) have been examined. The catalyst based on titania with a particle size of 20 nm and a platinum loading of 10 wt % has been found to have the CO oxidation rate 100 times higher than that on platinum black with a specific surface area of 30 m2/g. The catalysts are promising for use in catalytic air purification systems.

Transition Metal (Fe2O3, Co3O4 and NiO)-Promoted CuO-Based α-MnO2 Nanowire Catalysts for Low-Temperature CO Oxidation

As a toxic pollutant, carbon monoxide (CO) usually causes harmful effects on human health. Therefore, the thermally catalytic oxidation of CO has received extensive attention in recent years. The CuO-based catalysts have been widely investigated due to their availability. In this study, a series of transition metal oxides (Fe2O3, Co3O4 and NiO) promoted CuO-based catalysts supported on the α-MnO2 nanowire catalysts were prepared by the deposition precipitation method for catalytic CO oxidation reactions. The effects of the loaded transition metal type, the loading amount, and the calcination temperature on the catalytic performances were systematically investigated. Further catalyst characterization showed that the CuO/α-MnO2 catalyst modified with 3 wt% Co3O4 and calcined at 400 °C performed the highest CO catalytic activity (T90 = 75 °C) among the investigated catalysts. It was supposed that the loading of the Co3O4 dopant not only increased the content of oxygen vacancies in the catalyst but also increased the specific surface area and pore volume of the CuO/α-MnO2 nanowire catalyst, which would further enhance the catalytic activity. The CuO/α-MnO2 catalyst modified with 3 wt% NiO and calcined at 400 °C exhibited the highest surface adsorbed oxygen content and the best normalized reaction rate, but the specific surface area limited its activity. Therefore, the appropriate loading of the Co3O4 modifier could greatly enhance the activity of CuO/α-MnO2. This research could provide a reference method for constructing efficient low-temperature CO oxidation catalysts.

EFFECT OF CERTAIN CATALYTIC POISONS ON THE ACTIVITY OF CUPRUM-PALADIUM COMPLEXES APPLIED ON CARBON MATERIAL IN THE REACTION IN THE REACTION OF CARBON MONOXIDE OXIDATION BY AIR OXYGEN

Oxide and metal complex catalysts for low temperature gas-phase oxidation of carbon monoxide by air oxygen lose their activity under the action of chemical poisons such as SO2, H2S, PH3, H2O. We have developed a highly efficient Wacker-type catalyst in which the carrier is a carbon fiber material (CFM), the precursor of which was cellulose hydrate. For such a catalyst, there are no studies on the effect of catalytic poisons, namely SO2 and H2O, on its activity in the reaction of low-temperature oxidation of CO with oxygen. The morphology, elemental composition and adsorption properties of carbon fiber material and carbon monoxide oxidation catalyst are investigated. Pd(II)-Cu(II)/CFM relative to water vapor and sulfur dioxide, as well as their effect on the protective properties of the catalyst. SEM studies (scanning electron microscope) confirmed the morphology typical of CFM and found very small agglomerates in the case of the catalyst, which are formed by paratacamite Cu2(OH)3Cl crystallites caused by oxidation of the carbon surface by palladium (II). When applying the catalyst components, the fibers do not lose their shape, but the surface of the fibers is unevenly covered with impurities. Palladium (II) is reduced by a carbon surface by about 10%, agglomerates [Pdo]n are not observed, while fiber erosion increases and very small agglomerates are formed on the surface, which are formed by Cu2(OH)3Cl phase crystallites. Carbon material is generally characterized by a high content of carbon and oxygen, but their distribution is heterogeneous. In the analysis of adsorption isotherms, which are classified as type IV, it was found that CFM and the catalyst based on it belong to the microporous samples. It is proved that only at the relative humidity of the gas-air mixture, which is equal to 30% C &lt; MPCSO2 (20 mg/m3). Catalyst poisoning does not disrupt the catalytic process, but with increasing amount of absorbed sulfur dioxide (QSO2 ) the degree of conversion of carbon monoxide decreases and especially sharply at the absorption of 10.3⋅10–4 mol SO2. Thus, the results obtained on the effect of relative humidity and the amount of adsorbed by the catalyst SO2 on the activity of Pd(II)-Cu(II)/CFM catalyst, indicate a significant reduction in the degree of conversion of carbon monoxide. Therefore, in the case of applying of such a catalyst, for example in respiratory protection against CO, a preliminary stage of absorption of moisture and sulfur dioxide should be provided.

Sintering-resistant and highly active Au/SBA-15 catalyst for carbon monoxide oxidation

The low thermal stability of gold-based catalysts is a significant obstacle to their practical application, especially under demanding conditions, such as those prevailing in automotive exhaust gas converters. In this work, we demonstrate that it is possible to strongly anchor 2–3 nm size gold nanoparticles inside the pores of SBA-15 mesoporous silica. The Au/SBA-15 catalyst showed high thermal stability, even at a temperature of 700–800 °C. The gold was evenly distributed inside the SBA-15 mesopores using the adsorption of the [Au(en)2]Cl3 complex (en = ethylenediamine) in an alkaline environment. Due to the very small size of gold nanoparticles, the obtained catalyst was highly active in low-temperature CO oxidation. The high resistance of Au particles to sintering can be explained by the confinement effect and the strong metal-support interaction, induced during the catalyst precursor decomposition under an oxygen-free atmosphere at 400 °C. The carbonaceous layer, formed from ethylenediamine ligands decomposition, plays an essential role in stabilizing gold nanoparticles inside the SBA-15 pores. We believe that our findings may contribute to solving the problem of carbon monoxide emission during engine start-up.

Theoretical investigation of CO oxidation by single cobalt atom within two-dimensional porphyrin sheet

In this paper, the oxidation mechanism of carbon monoxide (CO) on two-dimensional porphyrin sheet within a single cobalt atom (Co-TDPs) was studied by density functional theory with dispersion (DFT-D). The stability of Co-TDPs at different temperatures was verified by first-principle molecular dynamics simulations. Absorption energies of reactant and product to anchor to the Co–N4 site showed CO and O2 adsorption to be stronger than the CO2 adsorption. In addition, the Langmuir–Hinshelwood, Eley–Rideal (ER), and ter-molecular Eley–Rideal (TER) mechanisms were used to investigate the reaction mechanisms of CO oxidation on Co-TDPs. The Langmuir–Hinshelwood (LH) and ER mechanisms were feasible reaction profiles of CO oxidation because of their smaller energy barrier. The results suggested that the Co-TDPS was acting as a catalyst for CO oxidation in the mild condition.

Oxygen deficient Ce doped CO supported on alumina catalyst for low-temperature CO oxidation in presence of H2O and SO2

The carbon monoxide (CO) oxidation has been carried out using Ce doped Co/Al2O3 prepared by coprecipitation followed by deposition precipitation. The 0.1 mol Ce doped Co supported on alumina showed maximum CO oxidation activity compared to the undoped catalyst at a low temperature. The physicochemical characteristics of synthesized catalysts were investigated by FTIR, XRD, Raman, XPS, 27Al solid-state NMR, H2-TPR, HR-TEM, etc. Ce doping promoted a distortion in the cobalt lattice structure. The distortion leads to an increase in reactive oxygen and the number of oxygen vacancies. In addition, Ce modification prevents the generation of the cobalt aluminate phase and stimulates the production of the Co3O4 active phase for CO oxidation. The presence of hexa and penta-coordinated alumina increases the defect and oxygen vacancy formation, which was responsible for a higher CO oxidation rate. The Ce doped Co/Al2O3 catalyst showed maximum water and SO2 tolerance due to the Ce doping. The mechanistic and kinetic details for CO oxidation have been explained by correlating with characterization.

Highly facile Co2+ and Mn3+ species supported on hydroxyapatite catalyst for carbon monoxide oxidation at a lower temperature

Highly facile Co2+ and Mn3+ species supported on hydroxyapatite catalyst for carbon monoxide oxidation at a lower temperature

Comparative activity of Platinum and Gold nanoparticles catalysts for Carbon monoxide oxidation

The activity of Pt and Au nanoparticles catalysts over titania support for carbon monoxide oxidation was investigated. Pt and Au catalysts were synthesised by a high-throughput physical vapour deposition methodology (HT-PVD). A parallel thermographic screening methodology, which enabled the quantification of the activity of Pt and Au catalysts for CO oxidation reaction, was applied. A particle size effect in the catalytic activity of Pt and Au was observed, with the smallest particles exhibiting the highest activity. The activity of Pt and Au catalysts increased with temperature. Au catalyst displayed high activity at 80 ℃, while Pt catalyst had higher activity at 170 ℃. Although CO oxidation on Pt and Au catalysts is particle size-dependent, results show that Au nanoparticles catalyst exhibits the strongest particles size dependence as compared to Pt catalyst.

Influence of Acid Modification of Natural Phlogopite on Catalytic Activity of Supported Pd(II)-Cu(II) Complexes in the Reaction of Oxidation of Carbon Monoxide by Atmospheric Oxygen

The paper presents original results on the of nitric acid concentrations effect on structure, morphology, protolytic properties and the activity of low-temperature carbon monoxide oxidation catalysts based on acid-modified phlogopite (Н-Phl-1) and K2PdCl4, Cu(NO3)2, KBr base components. The obtained samples were characterized by XRD, SEM, FT-IR spectroscopy and pH metric method. The obtained catalyst Pd(II)-Cu(II)/8H-Phl-1 can be recommended for use in respiratory devices.

Effect of surface acidity modulation on Pt/Al2O3 single atom catalyst for carbon monoxide oxidation and methanol decomposition

With ideal metal utilization efficiency and homogeneous active sites, single atom catalysts (SACs) have attracted extensive attention in heterogeneous catalysis field. The performance of SACs is highly dependent on the local coordination environment of metal single atoms. However, few works reported the effect of surface acidity modification on the performance of SACs such as Pt SACs which have been widely studied nowadays. In this work, a Pt/Al2O3 SAC has been successfully prepared using a bayerite Al(OH)3 as support through simple IWI method for Pt loading. Through post-modification of Pt/Al2O3 with acidic WO3 and basic MgO, the surface acidity of Pt/Al2O3 was tuned. Activity of CO oxidation and methanol decomposition on the modified catalysts has been evaluated. It was found that the catalytic performance was highly related to the surface acidity of Pt SACs. Basic MgO modified Pt/Al2O3 performed better in CO oxidation under the reaction condition with H2O. Acidic WO3 modified Pt/Al2O3 showed superior activity in methanol decomposition. Detailed characterization and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) study suggested that the positive H2O effect on CO oxidation was due to the mitigated formation of bicarbonate species on Pt/Al2O3 and WO3/Pt/Al2O3 catalysts and the promoted desorption of carbonate species from MgO/Pt/Al2O3. The superior methanol decomposition performance on WO3/Pt/Al2O3 was owing to its abundant oxygen vacancies and high resistance to carbonate accumulation. This study highlights the importance of surface acidity modulation of Pt SACs in heterogeneous catalysis and suggests that fine-tuning the surface acidity can be an effective strategy in new SACs development.

Co Anchored B36 Cluster as a Novel Single Atom Catalyst for Removing Toxic CO Molecules: A Mechanistic First‐Principles Study

AbstractThe catalytic oxidation of toxic carbon monoxide (CO) into carbon dioxide (CO2) is one of the most significant reactions in heterogeneous catalysis and industrial chemistry. Hence, finding efficient and cost‐effective catalysts for CO oxidation is very critical. In this study, the electronic and catalytic properties of a Co atom incorporated B36 cluster (Co@B36) are investigated by means of first‐principles calculations. The results show that the Co atom can seriously tune the properties of the B36 cluster due to significant hybridization between the 3d states of the Co atom and the B‐2p states of the surrounding B atoms. This induces a significant positive charge on the Co atom, providing an active site for O2 and CO molecules to attack. Furthermore, the well‐known mechanisms for CO oxidation, namely the Eley‐Rideal (ER), Langmuir‐Hinshelwood (LH), termolecular Eley‐Rideal (TER), and new Eley‐Rideal (NER), are taken into account in this work. According to our findings, the LH and TER mechanisms are the most energetically efficient routes for CO oxidation; however, the favored mechanism may be depending on the relative concentrations of CO and O2 molecules in the reaction mixture. The obtained activation energies through the TER and LH mechanisms are also comparable with those reported on noble metals. The findings of this work might help in the design and manufacture of noble‐metal free single atom catalysts for the removal of harmful CO molecules from the environment.

Structure-activity relationship of Pt catalyst on engineered ceria-alumina support for CO oxidation

In heterogeneous catalysis, the promotion of low temperature activity and enhancement of thermal stability simultaneously especially for precious metal catalysts is always highly demanded but very challenging. Herein we report a novel Pt catalyst on ceria-alumina (CeO2/Al2O3) support (Pt/CA-T) engineered by a two-step ceria deposition strategy, exhibiting superior thermal stability and low-temperature carbon monoxide (CO) oxidation activity after activation. Pt single sites anchored to engineered CeO2 edge sites are much more stable than that to CeO2 (111) surface, and such stable single sites can be transformed into highly active Pt clusters for efficient low-temperature CO oxidation. Active site identification indicates that the CO oxidation activity of different Pt sites follows such sequence: Pt cluster step sites ≈ Pt cluster terrace sites > Pt cluster corner sites ≫ Pt single sites on CeO2. The excellent low temperature activity of activated Pt/CA-T catalyst for CO oxidation is associated with its abundant Pt cluster step and terrace sites as well as rich Pt-CeO2 interfaces, which facilitate the adsorption of active CO species and superior oxygen activation/transfer ability. The present study provides new insights into the structure–activity relationship of Pt-CeO2-Al2O3 catalyst, which can also guide the preparation of other highly robust supported catalysts for important industrial applications.