Decay Of Catalytic Activity Research Articles

Heterogenous copper(II) schiff-base complex immobilized mesoporous silica catalyst for multicomponent biginelli reaction

A Copper(II) Schiff-base complex immobilized mesoporous silica-41 (Copper-Schiff base@MCM-41) was synthesized using the ultrasonication method. The formation of material with expected morphological and structural features was confirmed with various characterization techniques including UV-DRS, FTIR, LXRD, SEM, EDAX, ICP-AES, HR-TEM, BET, TGA-DTA, and ESR analyses. Furthermore, the Copper-Schiff base@MCM-41 catalyzed Biginelli reaction has performed under an eco-friendly solvent approach at room temperature, achieving high product yield. After the completion of the reaction, the catalyst was easily recovered using the filtration method and reused for another reaction, maintaining comparable product yield up to five repetitive cycles without any major catalytic activity decay. The exhibition of excellent catalytic activity towards 3,4-dihydropyrimidone derivatives with high product yield in a short time at room temperature proved that the Copper-Schiff base@MCM-41 is a more effective heterogeneous catalyst toward the Biginelli reaction compared to other catalysts. The plausible reaction mechanism has proposed based on the study.

In situ construction of chain-like PdAg/AgCl heterojunction electrocatalyst for ethylene glycol oxidation

In this paper, PdAg/AgCl heterojunction catalyst with chain structure has been synthesized using triblock copolymer P123 as protective agent and reducing agent. A small amount of AgCl is generated in situ, and finally the chain PdAg/AgCl heterojunction electrocatalyst is constructed. The chain structure mainly comes from the special chain structure of P123 itself. Electrochemical tests indicate that the PdAg/AgCl catalyst has good catalytic activity and stability for ethylene glycol, and its peak current density is 3.98 times that of commercial Pd/C catalysts. Compared with pure PdAg catalyst, the mass activity of glycol oxidation of the PdAg-AgCl catalyst has been increased by 1.52 times. After 500 cycles, the decay of catalytic activity decreased from 45.4% to 7.4%. The significant improvement of the catalytic activity and stability of the compound catalyst may be attributed to the co-catalytic effect of AgCl on the surface of PdAg and its special chain structure.

Recovery utilization of triolein for producing short chain alkane by combining biocatalysis and inorganic catalysis

ABSTRACT The production of waste cooking oil (WCO) has been increasing year by year and brought the serious environmental problems. A considerable research effort has been focused on the reuse of WCO. Utilizing the triolein existing in great quantity on olive oil and rapeseed oil is an effective strategy to realize the reuse of WCO. This work introduces a novel process for producing short-chain alkane from triolein based on the convenience of products separation. The continuous process including the hydrolysis of triolein into fatty acid by lipase, the oxidation of fatty acid for producing short-chain fatty acid, and the light-driven decarboxylation of short chain fatty acids was established to produce alkane. The feasibility of the proposed process was demonstrated using model substances. The influences of various operational parameters on hydrolysis, oxidation, and decarboxylation using model substances were studied systematically. The optimized yields of the hydrolysis, oxidation, and decarboxylation reactions were 78.7%, 52.1%, and 78.9%, respectively. The free lipase is reused under the optimal condition and observed that 31.9% decay in catalytic activity even 5 cycles. Immiscible reaction systems are used to facilitate separation of products. The decarboxylation with decarboxylase (CvFAP) for short-chain fatty acid lead to higher alkane yields in 15 min. In addition, the octane yield of 16.2% using triolein as the raw material was obtained in the continuous process. Although this approach results in a low total yield of gasoline, it highlights the potential applications in the production of hydrocarbon fuel with WCO.

Revealing the roles of hydrogen bond and Al2Cl7− anion species and kinetics for ionic liquid catalyzed transesterification of ethylene carbonate with methanol

The co-production of dimethyl carbonate (DMC) and ethylene glycol (EG) from the transesterification of ethylene carbonate (EC), which is synthesized from CO2 and ethylene oxide, with methanol has received researchers’ attention. Herein, this transformative process catalyzed with metal chloride-based ionic liquids (ILs) was investigated by employing spectroscopic characterizations in combination with kinetic studies. The interaction between cation and methanol via hydrogen bond and activation of carbonyl group in EC (or 2-hydroxyethyl methyl carbonate, HEMC) by metal chloride-contained anion were identified to show synergistic effects on catalytic transesterification. The chain length of alkyl group substituted at the 1-position N atom in imidazole ring affected the reaction rates due to the steric hindrance effect. Not AlCl4− but Al2Cl7− anion species in AlCl3-based IL exhibited activity in this transesterification, and the content of Al2Cl7− species was observed to show linear relationship with the transformative rates of both EC and HEMC. The kinetic studies also elucidated that the rates of both EC (or HEMC) and methanol are first-order dependent on their concentrations, and the formation of HEMC intermediate was the kinetic-relevant step with the activation barrier of 92 kJ/mol. As a result, the yield and selectivity of DMC (or EG) could reach up to around 95 % and 97 % with catalysis of [MDMIM]Cl/AlCl3 with AlCl3 molar fraction of 0.67 after 12 h reaction at 140 °C, which showed higher performance than any other tested metal chloride-based IL. Besides, no decay in catalytic activity and selectivity of this IL was observed after 10 times’ recycling.

Sulfonic Mesostructured SBA-15 Silicas for the Solvent-Free Production of Bio-Jet Fuel Precursors via Aldol Dimerization of Levulinic Acid

Sulfonic acid-functionalized mesostructured silicas have been evaluated in the solvent-free aldol dimerization of biomass-derived levulinic acid into bio-jet fuel precursors. These compounds produce branched alkanes in a subsequent hydrodeoxygenation process, with suitable properties for being a renewable alternative to conventional fossil aviation fuels. The combination of activity and selectivity toward the desired condensation products achieved over sulfonic acid-functionalized SBA-15 materials is superior to those displayed by other commercial solid acid catalysts. Enhanced textural properties provided by the mesoporous SBA-15 support contribute to such improved catalytic performance. The strength and loading of the mesoporous silica-supported sulfonic acid moieties are also important factors affecting the catalytic performance of the materials. Reaction conditions (temperature, time, and catalyst loading) have been optimized for propylsulfonic acid-functionalized mesostructured silica (Pr-SBA-15) by means of a response surface methodology, leading to a maximum yield to levulinic acid dimerization products of 58.4% (145 °C, 0.15 g of catalyst, 24 h, no solvent). Under these reaction conditions, conversion of levulinic acid is 61.1%, indicating excellent selectivity toward bio-jet fuel precursors. A small catalytic activity decay has been detected in reutilization experiments, attributed to the formation of organic deposits onto the catalyst surface. A mild acid washing of the catalyst allowed a significant recovery of the initial activity.

Insight into biodiesel synthesis using biocatalyst designed through lipase immobilization onto waste derived microporous carbonaceous support

The enzymatic conversion of vegetable oils is a cleaner alternative to the chemically catalysed transesterification processes. The present study describes the development of heterogeneous enzyme catalyst by immobilising lipase onto waste derived activated carbon (AC) support and its application in enzymatic transesterification. The study includes optimisation of enzymatic transesterification using indigenously prepared biocatalyst by considering four parameters. The main parameters affecting the biodiesel yield were recognized by statistical analysis using analysis of variance (ANOVA) and contribution factor. The obtained optimised conditions for maximum biodiesel yield were: catalyst loading 3 wt%, M/O ratio 6:1, time 5 h and temperature 20 °C. The ANOVA revealed that catalyst loading and temperature are the two most dominant parameters affecting the biodiesel yield significantly with contribution factor 68.99 and 27.95% respectively. The produced rubber seed oil methyl esters (RSOME) were characterised for estimating fuel properties and found to be comparable with conventional diesel. The catalyst is reused at the optimised condition and observed that 6–7% decay in catalytic activity after 7 cycles. Thus, AC supported lipase as a biocatalyst is highly effective in conversion of rubber seed oil (RSO) to biodiesel at optimised conditions derived using Taguchi approach.

Synthesis and architecture of polystyrene-supported Schiff base-palladium complex: Catalytic features and functions in diaryl urea preparation in conjunction with Suzuki-Miyaura cross-coupling reaction by reductive carbonylation

This work represents an efficient and unique phosphine-free approach for the polystyrene embedded Schiff-base palladium catalyzed diaryl urea synthesis and Suzuki-Miyaura cross-coupling reaction by reductive carbonylation process. The careful instrumental investigations with FE-SEM, TEM, EDAX, TGA, UV–Vis, FTIR, AAS, and elemental analysis precisely characterized the developed heterogeneous catalyst. Reaction parameters, like catalytic natures, starting materials, reaction environment, and solvent were examined sequentially. The present work has been adequately addressed to account for the generation and characterization of a new polymer bound Pd-catalyst and using it in the synthesis of diaryl ureas and diaryl ketones, with no substantial decay of catalytic activity.

A study of CO2 reforming of CH4 for coal delivered gases over Ni-based catalysts

NiCo-Mg/Al-1.7, Ni-Mg/Al-1.6, Ni-Mg/Al-0, and NiCo-Mg/Al-0.3 Ni-based catalysts were used to test their performance in CO2 reforming of CH4 reaction for a coal gas feed mainly containing CO and H2 as well as CO2 and CH4 at 900°C and the ambient pressure. Compared to the performance in ideal feed of CO2 and CH4 balanced with N2, the smaller reaction rate in the coal gas observed over all the catalysts was barely due to the lower concentration of CO2 and CH4 in the feed. NiCo-Mg/Al-1.7 catalyst showed the highest activity and stability among the four catalysts owing to its right metallic NiCo alloy sites to activate CH4 and the strong basic sites to activate CO2. The TPO of the spent catalyst after 24h TOS showed no carbon formation. The other three catalysts facilitated more or less various formats of carbon formation depending on different surface properties, leading to the decay of catalytic activity along the TOS. The coal gas feed that contains very small amount of O2 helped mitigate the formation of the inactive graphitic carbon, possibly because O2 burned the carbon of this kind. This study will improve the efficiency of using coal gas by converting its to-be-emitted CO2 and CH4 into valuable CO and H2.

Mo(VI) Complexes Immobilized on SBA-15 as an Efficient Catalyst for 1-Octene Epoxidation

SBA-15 materials were functionalized through a post-synthetic methodology with molybdenum-Schiff bases to provide catalytic activity in epoxidation reactions. Thus, glycidoxypropyl functionalities were first attached to the surface of the mesostructured silica, followed by the reaction of the immobilized oxirane groups with 2-amino propyl pyridine. This reaction allowed the obtaining of (hydroxypropyl)-2-aminomethyl pyridine ligands, directly tethered to the surface of the mesoporous silica-based SBA-15, which resulted in excellent chelating ligands to immobilize dioxo molydenum species by a reaction with MoO2(acac)2. This investigation comprises a thorough characterization of the process for building the immobilized molybdenum-Schiff base complexes, as well as the use of the obtained materials in 1-octene oxidation in the presence of organic hydroperoxides. These materials displayed high intrinsic catalytic activity in the epoxidation of 1-octene with organic hydroperoxides under a wide variety of conditions, although both the reaction solvent as well as the nature of the organic hydroperoxide, exerted a dramatic influence on the catalytic activity of these heterogeneous oxidation catalysts. Thus, whereas nonpolar solvents provided good epoxide yields with high efficiency in the use of the oxidant, polar solvents depressed the catalytic activity of the supported Mo-Schiff bases. These results have been ascribed to the competition with the solvent, when polar, for binding to the metal sites, thus avoiding the formation of the hydroperoxo-metal cycle and the epoxidation of the olefin. The catalysts presented here show good reusability with low catalytic activity decay after the first reuse.

Pt-based catalysts with tensile surface strain to boost activity

A Chinese–US research collaboration has developed fuel cell catalysts comprising biaxially strained platinum–lead core/Pt shell ‘nanoplates’, that offer enhanced oxygen reduction with minimal decay in catalytic activity.

Parametric effects and optimization on synthesis of iron (II) doped carbonaceous catalyst for the production of biodiesel

Synthesis of efficient and low cost heterogeneous catalyst for transesterification of triglycerides into esters is the need of the hour. The present study elaborates an indigenous development of ferromagnetic iron (II) doped carbonaceous catalyst (Fe/C) for the production of biodiesel from rubber seed oil. The parametric effects on the synthesis of Fe/C catalyst were studied to identify the most significant parameters affecting the biodiesel yield using Taguchi method. The doping process was optimised for maximum biodiesel yield considering four parameters viz. Impregnation time, temperature, catalyst content and agitation speed. The prepared catalyst was characterized using scanning electron microscopy (SEM), X-ray energy dispersive analysis (EDX), X-ray diffraction (XRD), thermo gravimetric analysis (TGA) and Fourier transform infrared spectrometer (FT-IR). The contribution factor revealed that agitation speed is the most influential parameter affecting the biodiesel yield followed by catalyst content, impregnation time and temperature. The maximum biodiesel yield observed in optimum condition of impregnation time 15h, impregnation temperature 40°C, catalyst content 5wt% and agitation speed 500rpm was 96.31%. The cost analysis of catalyst synthesis was done and found to be fairly economical. The reusability of the catalyst was tested to check the decay in catalytic activity at the optimised condition and found to decrease in activity by 0.8–1.2% after three cycles. Thus, the experimental results and characterization study confirm that indigenously developed carbonaceous catalyst from waste material doped with iron (II) is cost effective and capable of transesterifying the rubber seed oil into rubber seed methyl ester (RSME) with appreciable catalytic activity in reusability.

CO oxidation over gold nanoparticles on Mg(OH)<SUB align="right">2 and MgO subjected to different redox treatments

CO oxidation over gold nanoparticles (Au NPs) supported on magnesium oxide and magnesium hydroxide was studied at 30oC during 15 h. Gold (~2.6 wt.%) was supported by deposition precipitation on commercial magnesia followed by thermal treatment of selected samples in hydrogen or in oxygen at different temperatures: 350 or 500°C. The formation of Au NPs during the phase transition of Mg(OH)2 to MgO under either reduction or oxidation was monitored by in situ UV-Visible spectroscopy, online mass analysis and X-ray diffraction (XRD). The Mg(OH)2 to MgO phase transition led to the decapsulation of ∼30% of the gold that had been encapsulated by the Mg(OH)2species during gold deposition from aqueous solution on MgO. The initial activity on CO oxidation was similar for Au NPs supported either on Mg(OH)2 or on MgO, and was practically independent the type of redox pre-treatment. In turn, the catalytic activity decay with reaction time strongly depended on the type of redox pre-treatment, pre-oxidised catalysts being more stable than pre-reduced ones. It was suggested that sample pre-treatment affects activity decay via change of the CO2-catalyst interaction.

Surface chemistry and reactivity of Pd/BaCeO3∙2ZrO2 catalyst upon sulphur hydrothermal treatment for the total oxidation of methane

Starting from metal nitrates and glycine, 2% Pd/BaCeO3∙2ZrO2 catalyst was prepared by solution combustion synthesis and tested towards the total oxidation of methane. The catalyst underwent heavy sulphur-hydrothermal treatment at 800°C up to 450h. The catalyst was fully characterized (XRD, BET, SEM, O2-TPD, FTIR analyses and catalytic activity via CH4-TPC) every 150h. With ageing, catalytic activity tests demonstrated that the catalyst was heavily poisoned after 150h; then it recovered the catalytic activity after 300h, with a resulting performance better than the one reached in the fresh status. At the end of the sulphur-hydrothermal treatment, after 450h, the catalyst resulted heavily poisoned again. On the fresh catalyst surface, IR analysis of CO adsorption evidenced the formation of highly dispersed Pd metal clusters and Pd ions. After 300h of sulphur hydrothermal ageing, the increased catalytic activity towards methane combustion was probably supported by the segregation of ZrO2 and CeO2. Moreover, subsurface and bulk sulphate formation was detected with ageing and Pd metal species were not anymore available for CO coordination, probably because hindered by sulphate deposits. Prevailing ageing mechanisms resulted in the oxidation of the surface Pd metal particles and surface-bulk sulphates formation, the latter destroying the starting crystallographic structure, leading thus to the final catalytic activity decay.

Carbon Nanofibers As Catalytic Support for Application at the Positive Electrode of Metal-Air Batteries

Electrocatalysts for the oxygen reduction and the oxygen evolution reactions play a key role and determine the power and efficiency of energy conversion/storage devices, such as metal–air batteries or regenerative fuel cells. Metal–air batteries are gaining increased interest given their high power and energy density, versatility and reversibility. The air electrode catalysts must be bi-functional and highly active, being the reactions involved at this electrode critical for the overall efficiency of metal–air batteries. Oxygen electro-oxidation/electro-reduction presents slow kinetics, thus, in order to achieve high current densities, porous high surface area electrodes are required. Carbon materials are commonly used to increase the electrode surface area. The main disadvantage is that carbon corrosion processes can occur during the battery charging process, where oxygen is evolved at very positive potentials, thus affecting the stability of the catalysts. One way to reduce the carbon corrosion rate is the use of graphitized carbon materials. In the present work, carbon nanofibers (CNFs) were investigated as Pd catalyst support. CNFs were synthesized by the methane catalytic decomposition on a Ni-based catalyst at 700°C. The sulfite-complex method was used to obtain Pd nanoparticles supported on such CNFs and on a benchmark carbon support (Vulcan XC72R, BET 250 m2/g) for comparison purposes. The materials were physico-chemically characterized by using X-ray diffraction (XRD), transmission electron microscopy (TEM), nitrogen physisorption (BET) and thermogravimetric analysis (TGA) in air. The occurrence of highly crystalline graphitic carbon was obtained in the catalysts based on carbon nanofibers as support. TEM images evidenced the filamentous structure of the CNFs with an average diameter around 60 nm and an internal cavity (tubular fibers) of around 15 nm size. The arrangement of graphitic planes corresponded to fishbone-like nanofibers, i.e. showing a certain angle with respect to the growth axis. CNFs presented a BET surface area of ca. 100 m2/g. On the other hand, XRD patterns of Pd catalysts showed the typical fcc structure of palladium, with a crystallite size of around 6.5 nm for both supports (CNFs and Vulcan). The electrochemical behavior of these catalysts for both the oxygen reduction and oxygen evolution reactions was investigated in half-cell configuration in an alkaline solution (6 M KOH). Accelerated degradation tests consisting of potential cycling up to 2 V vs. RHE were also carried out in order to assess the stability of the catalysts under highly corrosive conditions. At the beginning of life, Pd catalyst supported on Vulcan showed slightly higher activity than the Pd/CNF catalyst. The electroactive area obtained by cyclic voltammetry was slightly higher for the Pd/Vulcan. This suggested a more homogeneous distribution of Pd nanoparticles on the surface of commercial support, as a consequence of its higher BET surface area. However, the accelerated degradation test led to a decay of catalytic activity in the case of Vulcan-supported Pd for the ORR, and quite significant for the OER. The decay of activity at the end of life was remarkably lower for the CNF-based Pd catalyst, pointing to a promising stability of the proposed catalyst. Acknowledgements CNR-ITAE authors acknowledge financial support from the European Community’s Seventh Framework Programme (FP7/2010-2013) under grant agreement NECOBAUT n. 314159. M.J.L. thanks the financial support from the Spanish Government throughout the project CTQ2011-28913-C02-01.

Visible light mediated cyclization of tertiary anilines with maleimides using nickel(II) oxide surface-modified titanium dioxide catalyst.

Surface-modified titanium dioxides by highly dispersed NiO particles have an extended absorption in the visible light region and a reduced hole-electron pair recombination than unmodified TiO2. They have now been successfully applied as highly active heterogeneous photocatalysts in the visible light mediated direct cyclization of tertiary anilines with maleimides to give tetrahydroquinoline products in moderate to high yields at ambient temperature. In contrast with unmodified titanium dioxide catalysts that are conventionally used in a stoichiometric amount in combination with UVA light, only a catalytic amount (1 mol %) of the surface-modified TiO2 catalyst is needed along with visible light to efficiently catalyze the reaction. Compared with transition-metal complexes such as Ru(bpy)3Cl2 or Ir(ppy)2(dtbbpy)PF6, advantages of these surface-modified titanium dioxides as photocatalyst include high catalytic activity, low cost, ease of recovering, and being able to be used for at least nine times without significant decay of catalytic activity.

Sulfonic acid heterogeneous catalysts for dehydration of C6-monosaccharides to 5-hydroxymethylfurfural in dimethyl sulfoxide

Sulfonic acid-functionalized heterogeneous catalysts have been evaluated in the catalytic dehydration of C 6 monosaccharides into 5-hydroxymethylfurfural (HMF) using dimethyl sulfoxide (DMSO) as solvent. Sulfonic commercial resin Amberlyst-70 was the most active catalyst, which was ascribed to its higher concentration of sulfonic acid sites as compared with the other catalysts, and it gave 93 mol% yield of HMF from fructose in 1 h. With glucose as the starting material, which is a much more difficult reaction, the reaction conditions (time, temperature, and catalyst loading) were optimized for Amberlyst-70 by a response surface methodology, which gave a maximum HMF yield of 33 mol% at 147 °C with 23 wt% catalyst loading based on glucose and 24 h reaction time. DMSO promotes the dehydration of glucose into anhydroglucose, which acts as a reservoir of the substrate to facilitate the production of HMF by reducing side reactions. Catalyst reuse without a regeneration treatment showed a gradual but not very significant decay in catalytic activity. Sulfonic acid-functionalized Amberlyst-70 was used in dimethyl sulfoxide (DMSO) as solvent for the catalytic dehydration of C 6 monosaccharides into 5-hydroxymethylfurfural (HMF), a biomass-derived platform molecule.

Combined gasification of coal and biomass in internal circulating fluidized bed

The paper addresses the combined gasification of biomass and brown coal in an internal circulating fluidized bed (ICFB) for generating a valuable producer gas.A primary method for tar abatement and gas improving was adopted, consisting in a Ni-based catalyst in the bed together with sand. The hydrogen concentration in the producer gas was high (up to 35% in the best case, >20% typically) demonstrating the validity of the ICFB process for co-gasification of coal with biomass. Higher H2 and CO contents and lower tar yields were obtained with greater coal loadings. The tar was reduced by up to three times when changing from inert to a partly catalytic bed, under steam gasification conditions. However, this good figure is contrasted by a rather fast decay in catalytic activity, and a rather low carbon conversion even in presence of the catalyst.A mathematical model based on thermodynamic computations predicts the trend and values of the measured gas concentrations at different steam/fuel ratios, providing useful indications for its optimal choice. The findings of the research reinforce the idea that dual bed gasification is suitable even when a relatively low reactivity fuel is used, such as the brown coal in this study.

Supported Manganese Dioxide Catalyst for Seawater Flue Gas Desulfurization Application

Ceramic-supported manganese dioxide catalyst, MnO2-ceramic, prepared by impregnation- precipitation method and calcined at 350 degree C, was exposed to flue gases to investigate the catalytic oxidation of sulphur dioxide in flue gas at seawater buffering system. The results showed that compared with acid treated ceramic, MnO2-ceramic gained 2%-46% higher Desulfurization efficiency in temperature range of 15-75 degree C. MnO2-ceramic exhibited 57% desulfurization efficiency at its favorable temperature (60 degree C) while ceramic showed 11% Desulfurization efficiency at 60 degree C. MnO2-ceramic was found to catalyze S(IV)oxidation even at low pH (pH<4) while the reaction rate of noncatalytic S(IV) oxidation is negligible under the identical conditions. No catalytic activity decay was observed after 40 hours’ run. XPS reveals that the Mn was in the oxidation state of +4 for the MnOx-ceramic. SEM-EDS and XRD indicated that the good catalytic activity of MnO2-ceramic at low temperature could be attributed to high dispersion of MnO2 on ceramic support. The high performance of MnO2-ceramic on the SO2 removal appeared to be promising in the seawater flue gas desulfurization industrial application when high sulfur coals were burned.

Poly(styrenesulphonic) acid: an active and reusable acid catalyst soluble in polar solvents

This article reports on the catalytic activity of soluble poly(styrenesulphonic) acid (PSSA) in three different reactions driven by acidic sites: tributyrin methanolysis, biodiesel synthesis and xylose dehydration to furfural. The PSSA catalyst, soluble in the polar media used in these reactions, displayed larger catalytic activity than other non-soluble sulphonic solid catalysts studied (Amberlyst 36, Amberlyst 70 and Nafion®-SAC13). The ultrafiltration of the used PSSA catalyst allowed retention and reutilisation of the catalyst for several runs. No significant decay in catalytic activity was observed for the three reaction repeats investigated. All these results demonstrated that PSSA, a material that can be obtained from polystyrene waste, is an excellent reusable catalyst for conducting reactions demanding acidic sites.

Total oxidation of CO at ambient temperature using copper manganese oxide catalysts prepared by a redox method

Binary copper manganese oxides were prepared by a novel redox method and their catalytic activity for CO oxidation at ambient temperature evaluated. The catalytic activity was found to be high, and compared favorably with a commercial Hopcalite catalyst. The most active catalyst was able to completely oxidize CO at ambient temperature. Catalytic activity decay, most likely due to carbon dioxide retention was observed. The catalysts were deactivated by moisture but expelling water at moderate temperatures easily restored their catalytic activity. The catalysts were characterized by means of BET, FE-SEM, TEM, EDAX, XPS, TPD and X-ray powder diffraction. The optimum copper loading was determined to be ∼9% of the manganese content.