Activity For Carbon Monoxide Oxidation Research Articles

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.

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.

Highly efficient Au/Fe2O3 for CO oxidation: The vital role of spongy Fe2O3 toward high catalytic activity and stability

Supported gold catalysts have drawn great attention for many decades due to their outstanding performance in remedying the environment from carbon monoxide (CO) pollution. In this study, due to the large surface area of spongy Fe2O3, fabricated by salt-assisted ultrasonic spray pyrolysis, a considerable amount of Au was loaded on spongy Fe2O3 compared to low-surface-area non-spongy Fe2O3. It is seen that the spongy Fe2O3 catalyst loaded with Au has an interface that can be extremely active for CO desorption and O2 activation. That means it has high catalytic activity in CO oxidation than non-spongy and low surface area Fe2O3 loaded with Au. Also, the incorporation of Au in low alkaline condition further enhances the interaction between Au and Fe2O3, providing more active sites. This made the catalyst to have better activity, good stability over 60 hrs, and there was no carbonate on its surface. It had full conversion at 30 °C on 120 L g-1h−1 with high TOF (2.2 s−1).

Dressing of Cu Atom over Nickel Cluster Stimulating the Poisoning-Free CO Oxidation: An Ab Initio Study.

In this work using first-principles calculations based on spin-polarized density functional theory (DFT), the role of the Cu atom in degrading the poisoning of carbon monoxide (CO) over NinCu clusters is unveiled. The search has been initiated with the examination of structural, magnetic, and electronic properties of Nin+1 and NinCu clusters (1 ≤ n ≤ 12). X-ray absorption near-edge structure (XANES) spectra of Ni K-edge are computed to extract the information on the oxidation states and coordination environment of metal sites of the clusters. This study is operated with the two forms of dispersion corrections, i.e., D2 and D3, with standard DFT (with LDA and GGA functionals) for the consideration of van der Waals interactions during CO adsorption. The PBE and PBE-D3 approaches are found to be capable of yielding the experimentally observed preferential site for CO adsorption. The effect of spin-polarization on the reactivity of transition metals (TMs) toward CO adsorption is crucially assessed by the electronic reactivity descriptors such as d-band center, d-band width, and fractional filling of d-band using a spin-polarized d-band center model. The effective charge transfer from Cu to Ni atoms makes Ni atoms more efficient of charge and is attributed to the degrading adsorption of CO over NinCu clusters. The Ni12Cu cluster stands out with good CO oxidation activity for the Langmuir-Hinshelwood (L-H) reaction pathway.

Using the Interaction between Copper and Manganese to Stabilize Copper Single-atom for CO Oxidation.

The interaction between Cu and Mn has been used to immobilize the Cu single-atom on MnO2 surface by redox-driven hydrolysis. Comprehensive structure and property characterizations demonstrate that the existence of an Cu-Mn interaction on the catalyst surface can effectively restrain the aggregation of Cu single atoms and improve carbon monoxide (CO) oxidation activity. The interaction of forming the Cu-O-Mn entity is beneficial for CO catalytic activity as the migration of reactive oxygen species and the coordination effect of active centers accelerate the reaction. In particular, 3%-Cu1 /MnO2 shows an oxygen storage capacity (OSC) value (342.75 μmol/g) more than ten times that of pure MnO2 (27.79 μmol/g) and has high CO catalytic activity (T90% =80 °C), it can maintain CO conversion of 95 % after 15 cycles. This work offers a reliable method for synthesizing Cu single-atom catalysts and deepens understanding of the interaction effect between single transition metal atoms and supports that can improve the catalytic activity of CO oxidation.

Catalytic oxidation of CO on noble metal-based catalysts.

Carbon monoxide (CO) catalytic oxidation has gained increasing interest in recent years due to its application prospects. The noble metal catalysts commonly exhibit outstanding CO catalytic oxidation activity. Therefore, this article reviewed the recent research on the application of noble metal catalysts in the catalytic oxidation of CO. The effects of catalyst support, dopant, and physicochemical properties on the catalytic activity for CO oxidation are summarized. The influence of the presence of water vapor and sulfur dioxide in the reaction atmosphere on the catalytic activity in CO oxidation is emphatically discussed. Moreover, this paper discussed several reaction mechanisms of CO catalytic oxidation on noble metal catalysts. Finally, the challenges of removing CO by catalytic oxidation in practical industrial flue gas are proposed.

Bimetallic Pt-Co Nanoparticle Deposited on Alumina for Simultaneous CO and Toluene Oxidation in the Presence of Moisture

Carbon monoxide (CO) and hydrocarbons (HCs) generally have competitive adsorption on the active site of noble-metal nano-catalysts, thus developing an effective way to reduce the passivation of competitive reaction with each other is an urgent problem. In this study, we successfully synthesized transition metal-noble metal (Pt-M) alloys via introducing inexpensive metal elements (M = Ni, Co and Cu) into Pt particles and then deposited on alumina support to form Pt-based catalysts. Subsequently, we choose CO and toluene as polluting gases to evaluate the catalytic activities of Pt-M/Al2O3 catalysts. Introducing inexpensive metal elements (M = Ni, Co, and Cu) significantly changed the physicochemical properties and catalytic activities of these Pt-based catalysts. It can be found that the Pt-Co/Al2O3 catalyst exhibited outstanding catalytic activity for CO and toluene oxidation under mixed gas atmosphere, compared with other Pt-based catalysts, which is due to the higher dispersity, more surface adsorption oxygen, and well redox ability. Surprisingly, H2O could promote the catalytic activities for CO/toluene co-oxidation over the Pt-Co/Al2O3 catalyst. Thus, the present synthetic strategy not only opens an avenue towards the synthesis of noble metal-based catalysts, but also provides an excellent tolerance to H2O in the catalytic process.

Photocatalytic CO Oxidation over Nanoparticulate Au-Modified TiO2 Aerogels: The Importance of Size and Intimacy

We determine the activity of catalytic carbon monoxide (CO) oxidation as a function of the size of gold nanoparticles (Au NP), their weight loading, and their interfacial intimacy with similarly si...

Recent Advances of Ceria‐Based Materials in the Oxidation of Carbon Monoxide

Carbon monoxide (CO) is a toxic and harmful gas pollutant. The realization of low‐temperature CO oxidation has been the focus of research. Also, CO oxidation as a typical model reaction is conducive to the in‐depth study of the catalytic reaction mechanism. Due to its unique oxygen storage/release capacity (OSC) and the easy transition between Ce3+ and Ce4+, CeO2 is widely used as a catalyst and catalyst support in many important reactions, especially the low‐temperature CO oxidation reaction. Herein, the application of cerium‐based materials in low‐temperature CO oxidation and CeO2 activity enhancement strategies in recent years are elaborated upon, including metal loading, adjustment of exposed facets of CeO2, and metal doping, through metal‐support interaction and the generation of oxygen vacancies on the CeO2 surface to improve the CO oxidation activity of cerium‐based catalysts. At the end of the review, the synthesis of Ce‐based materials and their applications and challenges in the field of CO oxidation are looked at.

Selection of Manganese oxide catalysts for catalytic oxidation of Carbon monoxide at ambient conditions

Abstract Carbon monoxide (CO) is one of the very poisonous gases present in the atmosphere and low temperature complete oxidation CO is very important process for all human being present in the environment. A catalytic converter was an emission control device that converts more toxic gases present in the automobile exhaust into less toxic gases by the catalytic reactions. The manganese oxide catalysts i.e. (XMn2O x , X = Ce, Co, Fe, Cu) are prepared into laboratory by the co-precipitation method followed by calcinations in reactive CO–air mixture and traditional calcinations conditions. The activity order of catalysts for CO oxidation is as follows: CuMn2O2 > CeMn2O2 > CoMn2O2 > FeMn2O2. Among all the prepared catalysts, the CuMn2O2 has showed that the best catalytic activity for CO oxidation at the low temperature. The complete oxidation of CO was achieved at 85 oC over CuMn 2RC catalyst. The calcinations strategies of precursors have great influenced on the activity of resulting catalysts. The CO oxidation activity was recognized to be a combination of factors including high surface area, active surface oxygen species and Mn(IV) cations. These results provide a novel thought to design the highly active CuMn2O2 catalyst.

Synthesis of CuMnOx catalysts by novel routes for selective catalytic oxidation of carbon monoxide

The ambient temperature catalytic oxidation of carbon monoxide (CO) is very important process for all living beings present in the atmosphere. Hopcalite (CuMnOx) is a mixed oxide of copper and manganese has been efficiently applied as a catalyst in the catalytic converter for CO oxidation. All the catalysts are prepared by the Co-precipitation method and characterized by the SEM-EDX, XRD, FTIR, BET and XPS technique. The ratio of Cu:Mn in CuMnOx catalyst was divided into three equal parts (Cu:Mn = 1:2, Cu:Mn = 1:1 and Cu:Mn = 2:1) and their performances for CO oxidation was also measured. The activity order of catalysts for CO oxidation was as follows: Cu2Mn1 < Cu1Mn1 < Cu1Mn2. In these catalysts the Cu1Mn2 has showed that the best catalytic activity for CO oxidation at a lower temperature. The calcinations strategies of precursors have great influences on the activity of resultant catalyst. All the catalysts are prepared in different calcinations conditions like reactive calcinations (RC) and traditional calcinations. The reactive calcinations strategy is one of the best calcinations strategies for the preparation of highly active catalysts. The stability of CuMnOx catalyst is also investigated in this research work.

Assessment of Manganese Oxide and Cobalt Oxide Catalysts for Three Way Catalytic Converter

Raising number of vehicles emits pollutants responsible for one third of total air pollution. Carbon monoxide (CO), unburned hydrocarbons (HC), and nitrogen oxides (NOx) are the main pollutants from petrol engines. It requires stringent vehicular emission norms to be followed for controlling it. Three Way Catalytic Converter (TWCC) contain Platinum Group Metals (PGMs) as catalyst to reduce exhaust emission and is widely used method that fulfills these standards. Because of high cost of PGMs and considerable advancement in metal oxide preparatory methods, metal oxide catalysts have gained more attraction. Manganese oxide (MnOx) and Cobalt Oxide (CoOx) have displayed impressive redox reactions at lower temperature. MnOx seems to be a suitable contender of Oxygen Storage Capacity (OSC) and Cobalt oxide (CoOx) has displayed an excellent catalytic activity for HC and CO oxidation. Hence, these catalysts attract the attention of researchers. Present paper assesses the prospect of MnOx and CoOx as catalysts for the TWCC for redox reactions of CO, HC and NOx and also in terms of OSC and T50 temperature. It is found that CoOx and MnOx both low cost metal oxide catalysts stand a good chance to replace the noble metals for TWCC.

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.

The Preparation of Palladium -Based Catalyst via Dielectric - Barrier Discharge (DBD) for Total Oxidation of n-butanol and CO at Low Temperature

In the present study, the total oxidation of n-butanol and carbon monoxide (CO) was investigated on 1 wt% Pd/(-Al2O3 catalysts which were prepared via the dielectric-barrier discharge (DBD) and wet-impregnation (WI) methods. All catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FT-IR), and Brunauer-Emmett-Teller method (BET). The catalytic activities in the total oxidation of VOCs (n-butanol) and CO under gas-phase conditions was measured. The results showed that the palladium catalysts prepared from DBD method exhibited higher activity in total oxidation of n-butanol and CO than catalysts prepared by WI method. This difference is due to better physicochemical properties of catalysts prepared by DBD method. For 1 wt% Pd loading, total oxidation of n-butanol and CO was achieved at 300 C and 175 C with the DBD method. Meanwhile, oxidation efficiency of the catalysts prepared by WI method is only approximately 90 % in two cases.

Biological H2 and CO oxidation activities are sensitive to compositional change of soil microbial communities.

Trace gas uptake by microorganisms controls the oxidative capacity of the troposphere, but little is known about how this important function is affected by changes in soil microbial diversity. This article bridges that knowledge gap by examining the response of the microbial community-level physiological profiles (CLPPs), carbon dioxide (CO2) production, and molecular hydrogen (H2) and carbon monoxide (CO) oxidation activities to manipulation of microbial diversity in soil microcosms. Microbial diversity was manipulated by mixing nonsterile and sterile soil with and without the addition of antibiotics. Nonsterile soil without antibiotics was used as a reference. Species composition changed significantly in soil microcosms as a result of dilution and antibiotic treatments, but there was no difference in species richness, according to PCR amplicon sequencing of the bacterial 16S rRNA gene. The CLPP was 15% higher in all dilution and antibiotic treatments than in reference microcosms, but the dilution treatment had no effect on CO2 production. Soil microcosms with dilution treatments had 58%-98% less H2 oxidation and 54%-99% lower CO oxidation, relative to reference microcosms, but did not differ among the antibiotic treatments. These results indicate that H2 and CO oxidation activities respond to compositional changes of microbial community in soil.

γ-Alumina-supported Pt17 cluster: controlled loading, geometrical structure, and size-specific catalytic activity for carbon monoxide and propylene oxidation.

Although Pt is extensively used as a catalyst to purify automotive exhaust gas, it is desirable to reduce Pt consumption through size reduction because Pt is a rare element and an expensive noble metal. In this study, we successfully loaded a Pt17 cluster on γ-alumina (γ-Al2O3) (Pt17/γ-Al2O3) using [Pt17(CO)12(PPh3)8]Cln (n = 1, 2) as a precursor. In addition, we demonstrated that Pt is not present in the form of an oxide in Pt17/γ-Al2O3 but instead has a framework structure as a metal cluster. Moreover, we revealed that Pt17/γ-Al2O3 exhibits higher catalytic activity for carbon monoxide and propylene oxidation than γ-Al2O3-supported larger Pt nanoparticles (PtNP/γ-Al2O3) prepared using the conventional impregnation method. Recently, our group discovered a simple method for synthesizing the precursor [Pt17(CO)12(PPh3)8]Cln. Furthermore, Pt17 is a Pt cluster within the size range associated with high catalytic activity. By combining our established synthesis and loading methods, other groups can conduct further research on Pt17/γ-Al2O3 to explore its catalytic activities in greater depth.

Ultrastable PtCo/Co3O4-SiO2 Nanocomposite with Active Lattice Oxygen for Superior Catalytic Activity toward CO Oxidation.

A nanostructural catalyst with long-term durability under harsh conditions is very important for an outstanding catalytic performance. Herein, a new ultrastable PtCo/Co3O4-SiO2 nanocatalyst was explored to improve the catalytic performance of carbon monoxide (CO) oxidation by virtue of the surface active lattice oxygen derived from strong metal-support interactions. Such a structure can overcome the issues of Co3O4-SiO2 inactivation by water vapor and the Pt inferior activity at low temperature. Further, Co3O4-SiO2 nanosheets endow superior structure stability under high temperatures of up to 800 °C, which gives long-term catalytic cyclability of PtCo/Co3O4-SiO2 nanocomposites for CO oxidation. Moreover, the large specific surface areas (294 m2 g-1) of the nanosheet structure can expose abundant surface active lattice oxygen, which significantly enhanced the catalytic activity of CO oxidation at 50 °C over 30 days without apparent aggregation of PtCo nanoparticles after 20 cycles from 50 to 400 °C. It can be expected to be a promising candidate as an ultrastable efficient catalyst.

Design of Ceria Catalysts for Low‐Temperature CO Oxidation

AbstractA catalyst active to carbon monoxide (CO) oxidation at low temperature is essential for environmental conservation, saving fuel and improvement of the quality of human life. Rational design of CO oxidation catalyst on the basis of comprehensive understanding of physicochemical properties of catalytic materials, rather than simply searching for the catalyst based on trial‐and‐error, is a promising approach to meet the increasingly stringent regulations. This review covers metal‐doped and ‐loaded system based on CeO2 catalysts as strategies to significantly improve CO oxidation activity at low temperature. When incorporated into CeO2 lattice, active metals significantly lower the oxygen vacancy formation energy (Evf) of the catalyst surface, resulting in high catalytic activities at low temperature. When the active metals are loaded on the CeO2 surface, many active sites could be acquired by increasing the dispersion, and the catalytic activity can be dramatically improved by newly introducing the interfacial sites between the metals and the CeO2 support. Doping the support could further improve this loaded system in terms of specific surface area, oxygen vacancy formation, and spillover effects. In this review, based on this knowledge, we propose a rational design approach to a robust low‐temperature CO oxidation catalysts. The desirable CO oxidation catalysts identified from the interplay between theoretical and experimental approaches would ultimately improve the quality of human life, and create potential economic benefits by alleviating air pollution.

Enhanced propane and carbon monoxide oxidation activity by structural interactions of CeO2 with MnOx/Nb2O5-x catalysts

A series of CeO2-MnOx/Nb2O5-x catalysts, with monoclinic Nb2O5-x (pre-calcined at 1025 °C) as the carrier, were synthesized and evaluated for catalytic oxidation of C3H8 and CO. Strong interactions between CeO2 and MnOx/Nb2O5-x were observed, and the catalyst with an optimal Mn/Ce ratio of 5.45 (1.24 wt% of CeO2) achieved 90% propane conversion at 290 °C and 90% CO conversion at 174 °C. The light-off temperature for 20% propane conversion occurred at ∼192 °C and 20% CO conversion occurred at ∼87 °C. The catalyst also showed very high stability during the long-term testing, even in the presence of water. Physicochemical characterizations and in-situ DRIFTS indicated that the addition of CeO2 greatly reduces the MnOx particle sizes, increases the dispersion of MnOx, and results in the formation of a Ce-Mn-O solid solution as well as a new Nb-Mn-Ce based phase. The interaction between Nb2O5-x and Ce-Mn mixed oxides with an optimized Mn/Ce ratio promotes the formation of oxygen vacancies and reduced species (Nb4+, Ce3+ and Mn3+), which leads to the upgrading of redox properties and enhances the ability for binding intermediates during reaction, contributing to the high oxidation activity of the catalysts.

Applications of silver nanocatalysts for low-temperature oxidation of carbon monoxide

Silver (Ag) is the best catalyst for many catalytic oxidation reactions. It is highly active for total oxidation of carbon monoxide (CO) at a lower temperature. The performance of silver catalysts depending upon their structure, surface active sites, and various Ag-O interactions. The other factors effects on the silver catalysts performances are synthesis method, treatment and reaction conditions and sizes of various Ag nanoparticles. The role of various silver species Ag0/Ag+ has examined and Ag0 as an active species originated to increases the catalytic activity at ambient conditions. The nano-sized Ag catalysts have concerned much interest because of their distinctive catalytic activity for different reactions. The silver catalysts highly dispersed over various support would be constructive for the best activity in CO oxidation at low temperatures. The particle size has certain effects on the catalytic performances of supported Ag catalysts. For active supports, the lattice oxygen presence in the support and electron transform among the silver‐oxygen and transition metals play a major role in the catalytic process. There are huge research articles are present on this matter, but very few numbers of review papers are available on this issue. So this is a gap fulfilled by this manuscript.