Activity For Carbon Monoxide Oxidation Research Articles

Revealing the intrinsic nature of Cu- and Ce-doped Mn3O4 catalysts with positive and negative effects on CO oxidation using operando DRIFTS-MS.

Aiming at the problem of the poor performance of an Mn-MOF-74-derived Mn3O4 catalyst in low-temperature carbon monoxide (CO) oxidation, copper (Cu) and cerium (Ce) elements were used to modify the Mn3O4 catalyst to improve its performance in low-temperature CO oxidation. According to the results of catalytic performance testing, the CO oxidation activity of the Cu0.3Mn2.7O4 catalyst was significantly improved compared with that of the pristine Mn3O4 catalyst, when a CO conversion rate of 90% was achieved at 118 °C. According to X-ray photoelectron spectroscopy and Brunauer-Emmett-Teller analyses, the (Mn2+ + Mn3+)/(Mn2+ + Mn3+ + Mn4+) ratio and the Oads/Ototal ratio increased after Cu doping, indicating promoted oxygen vacancy generation. In addition, the increased specific surface area was beneficial for the adsorption of reactant molecules and the exposure of active sites. According to H2-temperature-programmed reduction characterization, Cu doping significantly enhanced the performance of the Cu0.3Mn2.7O4 catalyst during low-temperature redox. Finally, these factors synergistically promoted the degradation of CO over the Cu0.3Mn2.7O4 catalyst. In addition, operando diffuse reflectance Fourier transform infrared spectroscopy results suggested the presence of more terminal-type oxygen, which is essential for the catalytic oxidation of CO on the surface of the Cu0.3Mn2.7O4 catalyst. Moreover, the Cu0.3Mn2.7O4 catalyst also showed excellent resistance to carbonate, and remarkable stability.

Water-assisted generation of catalytic interface: The case of interfacial Pt-FeOx(OH)y sites active in preferential carbon monoxide oxidation

The surface of supported heterogeneous catalysts often contains adsorbed water and hydroxyl groups even when water is not directly added to the reaction stream. Nonetheless, the reactivity of adsorbed water and hydroxyl groups is rarely considered. We demonstrate that water and hydroxyl groups can not only directly participate in the catalytic oxidation processes but are also able to generate and stabilize the catalytically active metal-oxide interface. We show that the reduction of Pt-Fe-supported catalysts with hydrogen in the presence of adsorbed water or steam allows for achieving one of the highest preferential carbon monoxide oxidation activities at ambient temperature. These conditions create active iron-associated hydroxyl groups next to platinum nanoparticles with enhanced reactivity towards carbon monoxide oxidation. Density functional theory calculations suggest that hydroxylation of oxidic iron species stabilizes the FeOx(OH)y/Pt interface, via strong metal-support interaction, which is confirmed by chemisorption measurements. Kinetic experiments, including those with 18O-labeled water, in combination with operando infrared spectroscopy, show that water and hydroxyl groups directly participate in preferential carbon monoxide oxidation. A quantitative correlation between the catalytic activity of Pt-FeOx(OH)y/γ-Al2O3 catalysts and the Fe2+ concentration, obtained using operando X-ray absorption spectroscopy, shows that the number of active Fe2+ sites and the carbon monoxide oxidation rate per active site can be significantly increased by water-assisted pretreatment with hydrogen. This work provides a new example of positive role of strong metal-support interaction for the design of more active catalysts.

Carbon Monoxide and Propylene Catalytic Oxidation Activity of Noble Metals (M = Pt, Pd, Ag, and Au) Loaded on the Surface of Ce0.875Zr0.125O2 (110)

With the advances in engine technology, the exhaust gas temperature of automobiles has further reduced, which in turn leads to an increase in the emissions of carbon monoxide (CO) and hydrocarbons (HCs). In order to understand the influence of CeO2-based catalysts loaded with different noble metals on the catalytic oxidation activity of CO and HCs, this study constructed catalyst models of Ce0.875Zr0.125O2 (100) surfaces loaded with Pt, Pd, Ag, and Au. The electronic density and state density structures of the catalysts were analyzed, and the reaction energy barriers for CO oxidation and C3H6 dehydrogenation oxidation on the catalyst surfaces were also calculated. Furthermore, the activity sequences of the catalysts were explored. The results revealed that after loading Pt, Pd, Ag, and Au atoms onto the catalyst surfaces, these noble metal atoms exhibited strong interactions with the catalyst surfaces, and electron transfer occurred between the noble metal atoms and the catalyst surfaces. Loading with noble metals can enhance the catalytic activity of CO oxidation, but it has little effect on the dehydrogenation oxidation of C3H6. Of the different noble metals, loading with Pd exhibits the best catalytic activity for both CO and C3H6 oxidation. This study elucidated the influence of noble metal doping on the catalytic activity of catalysts at the molecular level, providing theoretical guidance for the design of a new generation of green and efficient catalysts.

Enhanced CO oxidation performance over hierarchical flower-like Co3O4 based nanosheets via optimizing oxygen activation and CO chemisorption

Enhancing low-temperature activity is a focus for carbon monoxide (CO) elimination by catalytic oxidation. In this work, the hierarchical flower-like silver (Ag) modified cobalt oxides (Co3O4) nanosheets were prepared by solvothermal method and applied into catalytic CO oxidation. The doped Ag species in the form of AgCoO2 induced the prolongated surface Co–O bond and weaker bond intensity. Consequently, the oxygen activation/migration ability and redox capacity of Ag0.02Co were enhanced with more oxygen vacancies. The chemisorbed CO was preferentially converted to CO2 but not carbonates. The inhibited carbonates accumulation could avoid the coverage of active sites. According to Density functional theory (DFT) calculations, the electron transfer from AgCoO2 to Co3O4 promote electron donation ability of Co3O4 layer, benefiting for oxygen activation. Moreover, the longer Co–C and C–O bond length suggest the weakened chemisorption strength and higher active of CO molecule. The Ag modified Co3O4 exhibited more satisfactory activity at lower temperature. Typically, it realized 100% CO conversion at 90 °C, and displayed 6.3-fold higher reaction rate than pristine Co3O4 at 40 °C. Moreover, the Ag0.02Co exhibited outstanding long-term stability and water resistance. In summary, the optimized oxygen activation, CO chemisorption and interfacial electron transfer synergistically boosted the CO oxidation activity on Ag modified Co3O4.

Tip-activated single-atom catalysis: CO oxidation on Au adatom on oxidized rutile TiO2 surface.

Single-atom catalysis of carbon monoxide oxidation on metal-oxide surfaces is crucial for greenhouse recycling, automotive catalysis, and beyond, but reports of the atomic-scale mechanism are still scarce. Here, using scanning probe microscopy, we show that charging single gold atoms on oxidized rutile titanium dioxide surface, both positively and negatively, considerably promotes adsorption of carbon monoxide. No carbon monoxide adsorption is observed on neutral gold atoms. Two different carbon monoxide adsorption geometries on gold atoms are identified. We demonstrate full control over the redox state of adsorbed gold single atoms, carbon monoxide adsorption geometry, and carbon monoxide adsorption/desorption by the atomic force microscopy tip. On charged gold atoms, we activate Eley-Rideal oxidation reaction between carbon monoxide and a neighboring oxygen adatom by the tip. Our results provide unprecedented insights into carbon monoxide adsorption and suggest that the gold dual activity for carbon monoxide oxidation after electron or hole attachment is also the key ingredient in photocatalysis under realistic conditions.

High catalytic performance of CuCe/Ti for CO oxidation and the role of TiO2

CuCe/Ti-A and CuCe/Ti-R catalysts were prepared using anatase TiO2 (TiO2-A) and rutile TiO2 (TiO2-R) as supports using the incipient wetness impregnation method for the carbon monoxide (CO) oxidation reaction and were compared with a CuCe-C catalyst prepared using the co-precipitation method. The CuCe/Ti-A catalyst exhibited the highest activity, with complete CO conversion at 90 °C, when the gas hourly space velocity was 24000 ml·g−1·h−1 and the CO concentration was approximately 1% (vol). A series of characterizations of the catalysts revealed that the CuCe/Ti-A catalyst has a larger specific surface area, more Cu+ species and oxygen vacancies, and the Cu species of CuCe/Ti-A catalyst is more readily reduced. In situ FT-IR results indicate that the bicarbonate species generated on the CuCe/Ti-A catalyst have lower thermal stability than the carbonate species on CuCe/Ti-R, and will decompose more readily to form CO2. Therefore, CuCe/Ti-A has excellent catalytic activity for CO oxidation.

The Enhancement of CO Oxidation Performance and Stability in SO2 and H2S Environment on Pd-Au/FeOX/Al2O3 Catalysts.

Carbon monoxide (CO) is a colourless, odourless, and toxic gas. Long-term exposure to high concentrations of CO causes poisoning and even death; therefore, CO removal is particularly important. Current research has focused on the efficient and rapid removal of CO via low-temperature (ambient) catalytic oxidation. Gold nanoparticles are widely used catalysts for the high-efficiency removal of high concentrations of CO at ambient temperature. However, easy poisoning and inactivation due to the presence of SO2 and H2S affect its activity and practical application. In this study, a bimetallic catalyst, Pd-Au/FeOx/Al2O3, with a Au:Pd ratio of 2:1 (wt%) was formed by adding Pd nanoparticles to a highly active Au/FeOx/Al2O3 catalyst. Its analysis and characterisation proved that it has improved catalytic activity for CO oxidation and excellent stability. A total conversion of 2500 ppm of CO at -30 °C was achieved. Furthermore, at ambient temperature and a volume space velocity of 13,000 h-1, 20,000 ppm CO was fully converted and maintained for 132 min. Density functional theory (DFT) calculations and in situ FTIR analysis revealed that Pd-Au/FeOx/Al2O3 exhibited stronger resistance to SO2 and H2S adsorption than the Au/FeOx/Al2O3 catalyst. This study provides a reference for the practical application of a CO catalyst with high performance and high environmental stability.

Enhancing the Catalytic Activity of Mo(110) Surface via Its Alloying with Submonolayer to Multilayer Boron Films and Oxidation of the Alloy: A Case of (CO + O2) to CO2 Conversion

In-situ formation of boron thin films on the Mo(110) surface, as well as the formation of the molybdenum boride and its oxide and the trends of carbon monoxide catalytic oxidation on the substrates formed, have been studied in an ultra-high vacuum (UHV) by a set of surface-sensitive characterization techniques: Auger and X-ray photoelectron spectroscopy (AES, XPS), low-energy ion scattering (LEIS), reflection-absorption infrared spectroscopy (RAIRS), temperature-programmed desorption (TPD), electron energy loss spectroscopy (EELS) and work function measurements using the Anderson method. The boron deposited at Mo(110) via electron-beam deposition at a substrate temperature of 300 K grows as a 2D layer, at least in submonolayer coverage. Such a film is bound to the Mo(110) via polarized chemisorption bonds, dramatically changing the charge density at the substrate surface manifested by the Mo(110) surface plasmon damping. Upon annealing of the B-Mo(110) system, the boron diffuses into the Mo(110) bulk following a two-mode regime: (1) quite easy dissolution, starting at a temperature of about 450 K with an activation energy of 0.4 eV; and (2) formation of molybdenum boride at a temperature higher than 700 K with M-B interatomic bonding energy of 3.8 eV. The feature of the formed molybdenum boride is that there is quite notable carbon monoxide oxidation activity on its surface. A further dramatic increase of such an activity is achieved when the molybdenum boride is oxidized. The latter is attributed to more activated states of molecular orbitals of coadsorbed carbon monoxide and oxygen due to their enhanced interaction with both boron and oxygen species for MoxByOz ternary compound, compared to only boron for the Mox'By' double alloy.

Enhancing oxidation reaction over Pt-MnO2 catalyst by activation of surface oxygen

Formaldehyde (HCHO) and carbon monoxide (CO) are both common air pollutants and hazardous to human body. It is imperative to develop the catalyst that is able to efficiently remove these pollutants. In this work, we activated Pt-MnO2 under different conditions for highly active oxidation of HCHO and CO, and the catalyst activated under CO displayed superior performance. A suite of complementary characterizations revealed that the catalyst activated with CO created the highly dispersed Pt nanoparticles to maintain a more positively charged state of Pt, which appropriately weakens the Mn-O bonding strength in the adjacent region of Pt for efficient supply of active oxygen during the reaction. Compared with other catalysts activated under different conditions, the CO-activated Pt-MnO2 displays much higher activity for oxidation of HCHO and CO. This research contributes to elucidating the mechanism for regulating the oxidation activity of Pt-based catalyst.

Fabrication of supported Pt/CeO2 nanocatalysts doped with different elements for CO oxidation: theoretical and experimental studies.

Supported Pt/CeO2 catalysts have been widely used in carbon monoxide (CO) oxidation; however, the high oxygen vacancy formation energy (Evac) in the process leads to the poor performance of these catalysts. Herein, we explored different element (Pr, Cu, or N) doped CeO2 supports using Ce-based metal-organic frameworks (MOFs) as precursors via calcination treatment. The obtained CeO2 supports were used to load Pt nanoparticles. These catalysts were systematically characterized by various techniques, and they showed superior catalytic activity for CO oxidation compared to undoped catalysts which could be attributed to the formation of Ce3+, and high amounts of Oads/(Oads + Olat) and Ptδ+/Pttotal. Moreover, density functional theory calculations with on-site Coulomb interaction correction (DFT+U) were performed to provide atomic-scale insights into the reaction process by the Mars-van Krevelen (M-vK) mechanism, which revealed that the element-doped catalysts could simultaneously reduce the adsorption energies of CO and lower reaction energy barriers in the *OOCO associative pathway.

Facile Microwave Synthesis of Hierarchical Porous Copper Oxide and Its Catalytic Activity and Kinetics for Carbon Monoxide Oxidation.

The synthesis of copper oxide (CuO)-based nanomaterials has received a tremendous deal of interest in recent years. Particularly, the design and development of novel CuO structures with improved physical and chemical properties have attracted immense attention, especially for catalysis applications. We report on a rational, rapid, and surfactant-free microwave synthesis (MWS) of hierarchical porous copper oxide (HP-CuO) with a three-dimensional (3D) sponge-like topology using an MWS reactor. The activity of the microwave (MW)-synthesized HP-CuO catalysts for carbon monoxide (CO) oxidation was studied and compared to CuO prepared by the conventional heating method (CHM). Results showed that HP-CuO catalysts prepared by MWS for 10 and 30 min surpassed the CuO catalyst prepared by CHM, exhibiting T 80 of 98 and 115 °C, respectively, as compared to 185 °C of CuO prepared by CHM (T80 is the temperature corresponding to 80% CO conversion). In addition, the MW-synthesized HP-CuO catalysts outperformed the CHM-synthesized CuO, achieving a 100% CO conversion at 150 °C compared to 240 °C in the case of CuO prepared by CHM. Interestingly, the HP-CuO catalyst expressed workable CO conversion kinetics with a reaction rate of c.a.35 μmol s-1 g-1 at 150 °C and apparent activation energy (E a) of 82 kJ mol-1. The HP-CuO catalyst showed excellent cycling and long-term stabilities for CO oxidation up to 4 cycles and 72 h on the stream, respectively. The enhanced catalytic activity and stability of the HP-CuO catalyst appear to result from the unique topological and structural features of HP-CuO, which were revealed by SEM, XRD, Raman, BET, TGA, XPS, and TPR techniques.

Unravelling the real active center for CO oxidation-Cu+ or Cu3+: A case of model LaCuO3/MCF

Cu-based catalysts are one of the promising alternatives for industrial carbon monoxide (CO) oxidation applications. However, the exact active sites as well as their natures for CO oxidation have been still not fully understood yet. Herein, we designed and constructed a nano-size LaCuO3 perovskite oxide supported on inactive mesocellular siliceous foam (MCF), in which, the Cu species is featured by Cu3+. Then, LaCuO3-y/MCF with abundant Cu+ species was obtained by treating the as-prepared LaCuO3/MCF in H2/N2 flow. The catalytic activities of LaCuO3/MCF and LaCuO3-y/MCF were investigated for CO oxidation. The experimental results revealed that the Cu+ species rather than Cu3+ was the reactive site for CO oxidation. Moreover, density functional theory (DFT) calculations uncovered that the Cu+ species not only considerably facilitated the adsorption of CO and O2, but also dramatically reduced the desorption energy of CO2 from defective surface, thereby enhancing the catalytic activity of CO oxidation over Cu+ notably.

Promoting Metal–Support Interaction on Pt/TiO2 Catalyst by Antimony for Enhanced Carbon Monoxide Oxidation Activity at Room Temperature

Promoting Metal–Support Interaction on Pt/TiO₂ Catalyst by Antimony for Enhanced Carbon Monoxide Oxidation Activity at Room Temperature

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.

Pd-Nanoparticles Embedded Metal-Organic Framework-Derived Hierarchical Porous Carbon Nanosheets as Efficient Electrocatalysts for Carbon Monoxide Oxidation in Different Electrolytes.

Rational synthesis of Co-ZIF-67 metal-organic framework (MOF)-derived carbon-supported metal nanoparticles is essential for various energy and environmental applications; however, their catalytic activity toward carbon monoxide (CO) oxidation in various electrolytes is not yet emphasized. Co-ZIF-67-derived hierarchical porous carbon nanosheet-supported Pd nanocrystals (Pd/ZIF-67/C) were prepared using a simple microwave-irradiation approach followed by carbonization and etching. Mechanistically, during microwave irradiation, triethyleneamine provides abundant reducing gases that promote the formation of Pd nanoparticles/Co-Nx in porous carbon nanosheets with the assistance of ethylene glycol and also form a multimodal pore size. The electrocatalytic CO oxidation activity and stability of Pd/ZIF-67/C outperformed those of commercial Pd/C and Pt/C catalysts by (4.2 and 4.4, 4.0 and 2.7, 3.59 and 2.7) times in 0.1 M HClO4, 0.1 M KOH, and 0.1 M NaHCO3, respectively, due to the catalytic properties of Pd besides the conductivity of Co-Nx active sites and delicate porous structures of ZIF-67. Notably, using Pd/ZIF-67/C results in a higher CO oxidation activity than Pd/C and Pt/C. This study may pave the way for using MOF-supported multi-metallic nanoparticles for CO oxidation electrocatalysis.

Alloying Pd with Cu boosts hydrogen production via room-temperature electrochemical water-gas shift reaction

Room-temperature electrochemical water-gas shift (RT-EWGS) process provides a promising route for high purity hydrogen production under ambient conditions, in which the anodic carbon monoxide (CO) oxidation as the key and bottleneck-type reaction largely hinders the overall efficiency due to its sluggish reaction kinetics. It is of great significance to develop low cost and efficient anode electrocatalysts to enhance the hydrogen production via improving the CO oxidation activity, but it remains a great challenge. Herein, by alloying Pd with Cu, we achieve a high mass activity of 19.9 mA/mgPd for anodic CO oxidation at 0.3 V versus reversible hydrogen electrode (vs. RHE), which is over 330 times higher than that over pure Pd catalyst and significantly higher than the previously reported catalysts. Combined with density functional theory calculations, we find that the adsorbed CO (CO*) species is more likely to react with the adsorbed OH (OH*) rather than the OH- in the solution for PdCu alloy catalyst during the anodic CO oxidation process, and the introduction of Cu into Pd renders a weakened CO* adsorption along with an enhanced OH* adsorption, which significantly lower the overpotential via optimizing the anodic oxidation of CO pathway. This work provides a new direction for the design of efficient anode catalysts toward RT-EWGS with low energy input.

Efficient Solar‐Powered Interfacial Evaporation, Water Remediation, and Waste Conversion Based on a Tumbler‐Inspired, All‐Cellulose, and Monolithic Design

AbstractThe 3D steam generator with cold evaporation surface (CES) provides a means for high‐efficiency interfacial steam generation due to the low heat loss and continuous ambient energy input. However, the poor floating stability of CES steam generators when suffering wave slamming has limited their practical application in open water. Herein, a cellulose‐based monolithic aerogel integrated with three structural elements is developed inspired by tumblers, which can synchronously achieve outstanding antioverturning stability in waves and a high evaporation rate (4.21 kg m−2 h−1). A single‐stage solar water purification device is constructed based on the photothermal aerogel, which attains an ultra‐high daily water yield of ≈32.6 L m−2 and surpasses a large amount of single‐stage solar stills. The steam generator can also be used to purify wastewater containing Co2+ via adsorption. Gratifyingly, the Co3O4/C catalyst obtained from the pyrolysis of aerogels loaded with Co2+ exhibits good catalytic activity for carbon monoxide oxidation, demonstrating the potential for waste conversion. This work provides new insights into the design of solar steam generators used in open water, and offers a promising way for the disposal and utilization of contaminated steam generators after wastewater purification.

High-performance amperometric carbon monoxide sensor based on a xerogel-modified PtCr/C microelectrode

An amperometric biosensor based on a xerogel-modified PtCr/C microelectrode was developed for direct carbon monoxide (CO) detection. The effects of elemental Cr on the structural and electronic characteristics of the binary PtCr/C catalyst were characterized using various analytical techniques. Differential pulse voltammetry and amperometric measurements were performed to evaluate the electrocatalytic performance of the fabricated electrodes with respect to CO oxidation. The modified PtCr/C catalyst showed significantly improved electrocatalytic activity for CO oxidation, including a low applied potential of 0.3 V (vs. Ag/AgCl, high sensitivity of 12.5 nA μM−1 (standard deviation [SD] 0.52 nA μM−1)), excellent surface sensitivity of 726.6 nA μM−1 cm−2 (SD 30.4 nA μM−1 cm−2), and sufficiently high CO selectivity in the presence of other common metabolites. Modification of the PtCr/C-alloy catalyst surface with a fluorinated xerogel membrane minimized the effects of interfering species. Under optimal conditions, the xerogel-modified PtCr/C microelectrode exhibited a CO sensitivity of 8.82 nA μM−1 (SD 0.08 nA μM−1) and corresponding selectivity (logKCO,iamp) of < −5, −2.82 (SD 0.38), −3.16 (SD 0.03), − 2.57 (SD 0.05), −0.99 (SD 0.01), −2.02 (SD 0.01), and −1.79 (SD 0.05) for nitrite, ascorbic acid, uric acid, acetaminophen, dopamine, hydrogen peroxide, and nitric oxide. The xerogel-modified PtCr/C sensor was used to measure the CO directly generated on the surface of a living kidney in real time, and a CO concentration of 0.74 μM was estimated. Thus, our sensor can serve as a novel platform for developing high-performance electrochemical sensors suitable for practical applications.

Solid-State Construction of CuOx/Cu1.5Mn1.5O4 Nanocomposite with Abundant Surface CuOx Species and Oxygen Vacancies to Promote CO Oxidation Activity.

Carbon monoxide (CO) oxidation performance heavily depends on the surface-active species and the oxygen vacancies of nanocomposites. Herein, the CuOx/Cu1.5Mn1.5O4 were fabricated via solid-state strategy. It is manifested that the construction of CuOx/Cu1.5Mn1.5O4 nanocomposite can produce abundant surface CuOx species and a number of oxygen vacancies, resulting in substantially enhanced CO oxidation activity. The CO is completely converted to carbon dioxide (CO2) at 75 °C when CuOx/Cu1.5Mn1.5O4 nanocomposites were involved, which is higher than individual CuOx, MnOx, and Cu1.5Mn1.5O4. Density function theory (DFT) calculations suggest that CO and O2 are adsorbed on CuOx/Cu1.5Mn1.5O4 surface with relatively optimal adsorption energy, which is more beneficial for CO oxidation activity. This work presents an effective way to prepare heterogeneous metal oxides with promising application in catalysis.

Mechanism insights into CO oxidation over transition metal modified V2O5/TiO2 catalysts: A theoretical study

The V2O5/TiO2 based selective catalytic reduction (SCR) catalysts possess not only promising capability on the denitrification of nitrogen oxides (NOx), but also certain effects on the oxidation of carbon monoxide (CO) in the flue gas. Modification of traditional SCR catalysts with certain transition metals can further improve their catalytic oxidation ability of CO. Therefore, it is of great significance to reveal the catalytic oxidation mechanism of CO for developing modified SCR catalysts to achieve the co-removal of CO and NOx. Theoretical calculations based on density functional theory (DFT) were performed to probe the comprehensive reaction mechanism of CO oxidation on M doped V2O5/TiO2 catalysts (M = Mo, Fe, and Co). The whole CO oxidation cycles include three stages, i.e., the first CO oxidation, the re-oxidation of the surface, and the second CO oxidation. The terminal oxygen and the surface oxygen formed by the adsorbed O2 all play vital roles in the whole CO oxidation cycles. The activation barriers of the rate-determining steps for CO oxidation on Fe–V2O5/TiO2 and Co–V2O5/TiO2 are much lower than that of Mo–V2O5/TiO2, which indicates Fe and Co dopants can apparently promote the CO oxidation activities of the modified SCR catalysts. Meanwhile, the electronic structure analysis confirms that Fe and Co dopants can cause electron distribution change with strong oxidation ability at the active oxygen sites.