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Cross-linked amino-polystyrene was reacted with thiophene-2-carboxyldehyde followed by the reaction with different metal salts [Cu(II), Mn(II), V(IV), Fe(III) and Ni(II)] to form new heterogeneous polystyrene-anchored catalysts. The structures of the immobilized catalysts were established on the basis of CHNS, DRS, FTIR, AAS, EDX and EPR techniques. The catalytic activity of polystyrene-anchored catalysts was estimated for the oxidation of benzyl alcohol using tert-butyl hydroperoxide and hydrogen peroxide as oxidants. The influence of different reaction parameters like temperature, time, oxidant and the quantity of catalyst on the oxidation were investigated. Under optimized condition, the results show that TBHP as an oxidant provides 90% conversion with the nickel catalyst. The copper catalyst, when used with TBHP, demonstrated the highest selectivity for benzaldehyde, reaching 98%. Under optimal conditions, the catalysts can be reused four times without considerable loss in its activity. [ABSTRACT FROM AUTHOR]

Herein is studied the soot oxidation over platinum group metal oxide/CeO2–ZrO2 (PGM/CZ) catalysts. The ability to capture gas-phase oxygen was in sequence of Ru/CZ > Rh/CZ > Ir/CZ > Pt/CZ > Pd/CZ. A soot oxidation test by TG-DTA showed that Ru/CZ, Rh/CZ, and Ir/CZ are highly active catalysts. It was found that there is a good correlation between the ability to capture gas-phase oxygen and soot oxidation activity. TEM observation revealed that soot oxidation mainly occurs at the interface between soot and CZ surfaces. The Ea values and soot oxidation test using labelled oxygen suggest that highly active catalysts oxidize soot by CZ lattice oxygen. For Ir/CZ, soot oxidation at 270 °C occurred due to the reduction by soot. Ru/CZ and Rh/CZ captured gas-phase oxygen spontaneously below 250 °C, resulting in soot oxidation at 270 °C. H2-TPR results suggest that the reactivity of lattice oxygen in the CZ surface, improved by PGM, is also related to soot oxidation activity. This suggests that the ability to capture gas-phase oxygen and the reactivity of lattice oxygen in the CZ surface determine the soot oxidation activity, and that Ru, Rh, and Ir have the effect of enhancing these properties. [ABSTRACT FROM AUTHOR]

This work is concerned with the cyanide removal from aqueous solution by oxidation with hydrogen peroxide H2O2 catalyzed by copper zinc oxide (CuO-ZnO) nanoparticles prepared by co-precipitation method. The influences of catalyst dose, hydrogen peroxide concentration, temperature, and catalyst stability on cyanide removal were examined. The use of CuO-ZnO nanoparticles made it possible to increase the reaction rate, thus showing good catalytic activity. The cyanide removal percentage was increased after 75 minutes of reaction time from 70% to 100% by raising the catalyst dose from 0.25 g/L to 1.0 g/L. Increasing the temperature from 24 °C to 35 °C enhanced cyanide removal rate, the apparent activation energy was then found to be equal to 48 KJ/mol. The nanocatalyst was used again for four successive times and exhibited good stability. The kinetics of cyanide elimination was found to be pseudo-first order with respect to cyanide. [ABSTRACT FROM AUTHOR]

Four-component oxide catalysts MnOx–CuO–ZrO2–CeO2 are synthesized by co-precipitation with varying the calcination temperature from 400 °C to 800 °C. Formation and decomposition processes in mixed oxides are studied by X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. The redox properties of the obtained samples are tested by temperature-programmed hydrogen reduction, and the catalytic characteristics are examined in the CO oxidation reaction. At 400-600 °C homogeneous solid solution MnxCuyZrzCeqO2 with the fluorite structure is formed. Temperature elevation to 700-800 °C facilitates the gradual decomposition of initial oxide, with manganese and copper cations leaving its composition in the form of highly dispersed CuO and CuxMn3–xO4 particles. The occurrence of different active states in the catalyst and their transitions into each other under the temperature effect is shown to maintain the high activity in the CO oxidation reaction up to 800 °C. [ABSTRACT FROM AUTHOR]

The development of heterogeneous catalysts for the selective direct transformation of methane (CH4) remains a challenge because of the difficulty in activating the strong C–H bond and controlling selectivity to target products. The effect of various metal phosphate catalysts (37 examples) on the direct oxidation of CH4 to formaldehyde (HCHO) with molecular oxygen (O2) as the sole oxidant was studied using a fixed-bed flow reactor, and the effectiveness of the copper phosphate catalysts was confirmed. Four crystalline copper phosphates (Cu2P2O7, Cu3(PO4)2, Cu2(P4O12), and Cu4O-(PO4)2) with different Cu coordination geometries and Cu/P ratios were synthesized from Cu-(OAc)2·H2O and (NH4)2HPO4, and the dependence of CH4 oxidation on their structures, as well as that on the structure of CuO, was investigated. The Cu/P molar ratio strongly affected the oxidation catalysis; CH4 conversion increased with increasing Cu/P molar ratio, although the selectivity to HCHO decreased. Among the investigated Cu-based catalysts and metal phosphate nanoparticles (FePO4 and BiPO4), monoclinic Cu2P2O7, which has a Cu/P ratio of 1/1, exhibited the highest HCHO yield. The catalytic activity of Cu2P2O7 was improved by changing the copper source to Cu-(NO3)2·3H2O due to the surface nanostructure control. On the basis of mechanistic studies that include catalyst effect, kinetics, isotope-labeling, and pulse reaction experiments, as well as infrared spectroscopic analyses of adsorbed probe molecules, (i) surface lattice oxygen species of Cu2P2O7 possibly react with CH4 to give HCHO as the primary product and (ii) the surface redox-active Lewis acidic Cu2+ sites and weakly basic phosphate units on Cu2P2O7 play important roles in the C–H activation and the suppression of overoxidation to CO2, respectively. Density functional theory calculations revealed that the vacancy formation energies at oxygen sites in β-Cu2P2O7, which was formed by the phase transition of α-Cu2P2O7 under the catalytic conditions, were lower than those in α-Cu2P2O7. Such a superior oxygen-transfer ability likely contributes to the high catalytic performance and durability of Cu2P2O7 for the oxidation of CH4 to HCHO. [ABSTRACT FROM AUTHOR]

Methane is an abundant and relatively clean fossil fuel resource; therefore, its utilization as a chemical feedstock has a major impact on the chemical industry. However, its inert nature makes direct conversion into value-added products difficult under mild conditions. Compared to the gas-phase selective oxidation of methane, there have been several recent advances in the liquid-phase conversion of methane. This review categorizes the reports on the liquid-phase selective oxidation of methane according to the solvent and oxidant used. The advantages and disadvantages of each approach are discussed. High yields of methyl bisulfate as a methanol precursor can be achieved using SO3 in sulfuric acid; however, more attention should be paid to the separation process and overall economic analysis. However, the aqueous-phase selective oxidation of methane with in situ generated H2O2 is quite promising from an environmental point of view, provided that an economical reducing agent can be used. Based on the current state-of-the-art on this topic, directions for future research are proposed. [ABSTRACT FROM AUTHOR]

The removal of sulfur- and nitrogen-containing compounds present in fuels is and will be crucial to accomplish actual strict regulations to avoid environmental and humanity health adversities. The conventional hydrodesulfurization and hydrodenitrogenation processes conducted by refineries are limited due to severe operating conditions, and even more importantly, they are inefficient for simultaneously removing nitrogen- and sulfur-containing compounds in fuels. On the other hand, non-hydrogen technologies are beneficial in terms of mild operating conditions, and during the last two decades, some successful works have shown that these can be highly effective at efficiently removing both sulfur- and nitrogen-containing compounds from liquid fuels. For more than four decades, extensive research (thousands of publications since the 1980s) has been dedicated to developing remote desulfurization technologies without taking into consideration the presence of a complex fuel matrix, or even taking into account the presence of other harmful pollutant elements, such as nitrogen. Even more recently, several effective non-hydrogen denitrogenation processes have been reported without considering the presence of sulfur compounds. This review paper is a reflection on the limited work that has been successfully performed to simultaneously remove sulfur- and nitrogen-containing compounds from fuels. An evaluation of different methodologies (adsorption, extraction, oxidative (photo)catalysis, ultrasound-assisted oxidation) is presented here. Furthermore, this review intends to define new future strategies that will allow the design of more suitable and economical technologies, effectively conciliating desulfurization and denitrogenation processes to produce more sustainable fuels. [ABSTRACT FROM AUTHOR]

TiO2−CeO2−Pt hollow nanospheres (1 wt‐% Pt) are realized using a liquid‐phase strategy using NaCl as a template. The NaCl template is first coated with TiO2 and thereafter with CeO2 via the hydrolyzation of TiCl(OiPr)3 and Ce(OiPr)4 as suitable alkoxides. Finally, the NaCl template is removed by washing with water. The resulting @TiO2−CeO2 hollow nanospheres (□: inner cavity) exhibit an outer diameter of 140–180 nm, a wall thickness of 30–40 nm, an inner cavity of 80–100 nm, a specific surface area of 210 m2/g, a pore volume and area of 0.08 cm3/g and 191 m2/g, mainly with micropores ≥5 Å and ≤14 Å. The hollow nanosphere support is impregnated with Pt nanoparticles, using two different methods – a wet‐chemical deposition (Pt(ac)2, acetone, 25 °C) and a supercritical fluid reactive deposition (SFRD) process ([Pt(COD)Me2], supercritical CO2, 80 °C, 15.6 MPa) resulting in an uniform size distribution with Pt nanoparticles 2.5±0.1 nm (TiO2−CeO2−PtWCD) and 2.3±0.1 nm (TiO2−CeO2−PtSFRD) in size. The catalytic properties of the TiO2−CeO2−Pt hollow nanospheres are evaluated for CO oxidation between 50 and 500 °C. A promising catalytic activity and stable light‐out/light‐off temperatures are observed especially for the TiO2−CeO2−PtSFRD sample, indicating the suitability of hollow nanospheres as high‐porosity catalyst material. [ABSTRACT FROM AUTHOR]

Furfurylamines are converted to 3‐hydroxypyridines by 1) oxidation with hydrogen peroxide to ring‐opened intermediates, with 2) a subsequent acid‐mediated cyclization/aromatization catalysed by the acidic and recyclable Aquivion catalyst eliminating neutralization steps. For substituted furfurylamines, the electronic effect of the substituents influence the conversion rate and this effect was correlated with Hammet's constants. Conversions up to 60 % were obtained for the most reactive furfurylamines. [ABSTRACT FROM AUTHOR]

In this study, titanium-containing MCM-41 has been synthesized through wet impregnation and direct hydrothermal synthesis methods and used for the oxidation of secondary alcohol to a carbonyl compound in the presence of hydrogen peroxide. FT-IR, BET, XRD, SEM–EDX, and Raman spectroscopy has been used to characterize the prepared mesostructured catalysts and the obtained results revealed that the Ti was successfully inserted into the MCM-41 framework. XRD results showed that the hexagonal structure of the mesoporous material of all samples was preserved, but the Ti-MCM-41(20) showed a slightly distorted porous structure. Oxidation of 1-phényl-1-propanol using aqueous 30% H2O2 as an oxidant in dichloromethane was also performed to investigate the catalytic performance. Ti inserted directly into the mesoporous silica gel showed better catalytic performance (95–98%). The Ti/Al-MCM-41 prepared by impregnation exhibits significantly high catalytic activity (99%) for secondary alcohol oxidation and showed excellent regeneration ability. MCM-41 may have considerable potential application in future industrial applications. [ABSTRACT FROM AUTHOR]

In this study, titanium-containing MCM-41 has been synthesized through wet impregnation and direct hydrothermal synthesis methods and used for the oxidation of secondary alcohol to a carbonyl compound in the presence of hydrogen peroxide. FT-IR, BET, XRD, SEM–EDX, and Raman spectroscopy has been used to characterize the prepared mesostructured catalysts and the obtained results revealed that the Ti was successfully inserted into the MCM-41 framework. XRD results showed that the hexagonal structure of the mesoporous material of all samples was preserved, but the Ti-MCM-41(20) showed a slightly distorted porous structure. Oxidation of 1-phényl-1-propanol using aqueous 30% H2O2 as an oxidant in dichloromethane was also performed to investigate the catalytic performance. Ti inserted directly into the mesoporous silica gel showed better catalytic performance (95–98%). The Ti/Al-MCM-41 prepared by impregnation exhibits significantly high catalytic activity (99%) for secondary alcohol oxidation and showed excellent regeneration ability. MCM-41 may have considerable potential application in future industrial applications. [ABSTRACT FROM AUTHOR]

The thermal stability and CO oxidation activity of a non-equilibrium Pd--Ru alloy obtained by leaching Al--Pd--Ru alloy (3/2 approximant, P40 phase: Al72Pd16.4Ru11.6 (at%)) with 20 mass% NaOH aqueous solution were investigated. When the Pd--Ru alloy was annealed under a He or H2 atmosphere, phase separation of the Pd--Ru alloy proceeded under H2 at 500°C, whereas the non-equilibrium state was relatively stable under He at temperatures as high as 500°C. In addition, the Pd--Ru alloy sample annealed under He (at 300 or 500°C) showed substantially greater CO oxidation activity than those annealed under H2 (at 300 or 500°C). The results suggested that there is a more suitable microstructure of Pd--Ru alloy in the nanocrystals for CO oxidation than the solid solution state or the phase-separated state. [ABSTRACT FROM AUTHOR]

2-Hydroxybenzyl alcohol is an important active pharmaceutical ingredient for the production of many drugs, in particular gastrodin, which has a wide range of beneficial effects on epilepsy, Alzheimer’s disease, Parkinson’s disease, affective disorders, cerebral ischemia, cognitive disorders. It is known that 2- and 4-hydroxybenzyl alcohols and mixtures of both compounds are obtained by the interaction of phenol with formaldehyde in the presence of basic catalysts. Due to its high reactivity with formaldehyde, the isolation of pure compounds from the reaction mixtures obtained during the interaction of phenol with formaldehyde is a big problem. Isolation of 2-hydroxybenzyl alcohol in pure form from reaction mixtures is possible only using processes that cannot be carried out on an industrial scale and is accompanied by low yields of the target product. It is possible to get rid of these problems by means of the process of direct oxidation of the 2-hydroxytoluene with ozone in the liquid phase since methods of selective ozonation of methylbenzene to the oxygen derivatives are already known. Therefore, the development of a new low-temperature synthesis of 2-hydroxybenzyl alcohol using ozone is an urgent task. The aim of the work is to study the reaction of the oxidation of 2-hydroxytoluene by ozone in a solution of a stop reagent and catalytic impurities of compounds of transition metals and mineral acids for the development of a new method of synthesis of 2-hydroxybenzyl alcohol. Materials and methods. For the experiments, acetic anhydride of p. a. qualification was used; glacial acetic acid of puriss. qualification, which before use was purified by distillation under vacuum in the presence of potassium permanganate, 2-hydroxytoluene of puriss. Qualification, manganese (II) acetate of pur. Qualification, sulfuric and phosphoric acids of puriss. qualification. To determine the concentration of ozone in the gas phase, a spectrophotometric method was used, based on the measurement of the optical density of the gas flow in the UV region. For this purpose, a spectrophotometer SF-46 LOMO was used, in the measuring chamber of which a flow cuvette with quartz windows was installed. The material of the cuvette was Teflon. Continuous monitoring of the current concentration of ozone, with the recording of the analysis results in the form of a kinetic curve, was carried out when ozone-containing gas passed through the curette at a certain wavelength of a monochromatic light source. Results. The reaction of oxidation of 2-hydroxytoluene by ozone in a solution of the stop reagent – acetic anhydride was studied. It was shown that in the presence of sulfuric acid, it was possible to carry out direct ozonation of 2-hydroxytoluene to 2-hydroxybenzyl alcohol, which was formed in the kind of 2-acetoxybenzyl acetate with a yield of 13.0 %. The main products of the reaction under these conditions are aliphatic compounds, which are formed after the destruction of the aromatic ring. The selectivity of oxidation by alcohol was significantly increased when a catalyst – manganese (II) acetate – was added to the system. In its presence, a catalytic system As2O – H2SO4 – Mn(III) was created, which prevents ozonolysis and directed oxidation mainly to the methyl group of the substrate with the formation of 2-acetoxybenzyl acetate with a yield of 63.2 %. Conclusions. An environmentally friendly, low-temperature method for the synthesis of 2-hydroxybenzyl alcohol was developed by conducting the oxidation of 2-hydroxytoluene with ozone in a solution of the stop reagent – acetic anhydride in the presence of sulfuric acid and manganese (II) acetate.

Ruthenium-based compounds are efficient catalysts to enhance combustion performance and suppress soot emission. However, systematic mechanism and in-situ research on reducing soot are rarely addressed. In this study, ruthenium acetylacetonate (Ru(C5H7O2)3, Ru(acac)3) was utilized as the catalyst precursor in different concentration conditions to investigate its impacts on the size, volume, and morphology of the soot particles in the ethylene flames with central toluene injection. The soot particles were detected by in-situ small-angle X-ray scattering (SAXS) and ex-situ transmission electron microscopy (TEM). This study confirms that Ru(acac)3 can suppress the surface growth for the primary soot particles, but no significant change of the morphology has been discovered for the aggregates. Compared with the undoped flame, the volume of the soot particles in the Ru(acac)3-doped flames is lower and the particle size is smaller, indicating a valid inhibition effect of Ru(acac)3 on the soot emission by affecting its surface growth and oxidation process. Despite the remarkable distinction between the undoped and doped flames, no obvious difference is found between the flames with different catalyst concentrations. [ABSTRACT FROM AUTHOR]

The chemistry of hypervalent iodine reagents has now become quite valuable due to the reactivity of these compounds under mild reaction conditions and their resemblance in chemical properties to transition metals. The environmentally friendly nature of these reagents makes them suitable for Green Chemistry. Reagents with a dual nature, such as iodine(III) reagents, are capable electrophiles, while iodine(V) reagents are known for their strong oxidant behavior. Various iodine(V) reagents including IBX and DMP have been used as oxidants in organic synthesis either in stoichiometric or in catalytic amounts. In this review article, we describe various oxidation reactions induced by iodine(V) reagents reported in the past decade. [ABSTRACT FROM AUTHOR]

In the present study, enhanced wet oxidation of excess sludge from pharmaceutical wastewater by NaOH as an alkaline homogeneous catalyst was investigated. The experiments were carried out in a stainless-steel batch autoclave reactor. The highest volatile suspended solids (VSS) removal rate, 95.2%, was achieved at 260 °C within 60 min with an initial oxygen pressure of 1.0 MPa and NaOH 0.5 g·L−1. Simultaneously, the chemical oxygen demand (COD) removal rate of 57.3% was reached. The increase in volatile fatty acids (VFAs) demonstrated that the degradation of sludge was greatly accelerated by NaOH. Interestingly, the production of acetic acid, an intermediate by-product generated from the oxidation of organic compounds, increased significantly. These results illustrated that NaOH is a promising catalyst for the utilization of wet oxidation liquid of excess sludge as a carbon source for the treatment of wastewater. [ABSTRACT FROM AUTHOR]

Organic dyes used to shade numerous materials on an industrial level causes water pollution. To meet the need for the removal of the dye-laden water the mechanistic methodology is developed in which catalyst (ZnO), oxidizer (H2O2), and irradiation of low dose (4 KGy) are involved. Oxidizers and catalysts are characterized for surface morphology by SEM, functional groups by FTIR, crystallinity by XRD, particle size by PSA, and for elemental ratio by EDX. A solution ranging from 2 ppm to 8 ppm of Congo red (CR) dye, ZnO (100 μg) as a catalyst, H2O2 (100 μL), as an oxidizer, and 4 KGy energy radiations were used during the degradation analysis for 30, 60, 90, and 120 min. The enhanced effect is shown by using the oxidizer, catalyst, and irradiation at a time. Moreover, it shows a degradation of 99 % for 2 ppm and 4 ppm within 60 min while 6 ppm almost 99 % within 90 min, and 8 ppm almost 96.76 % within 120 min. The established mechanistic methodology can also be applied to actual aqueous industrial samples. [ABSTRACT FROM AUTHOR]

A series of Fe3BO6–xCeO2 (x = 1, 5, 10, 20% by mole) mixtures was prepared via ball-milling process. The physicochemical properties of the mixtures have been characterized by X-ray diffraction, Fourier Transform Infrared Spectra, Scanning Electron Microscopy, Energy Dispersive X-Ray Spectroscopy, and N2 Adsorption–Desorption techniques. The results showed that CeO2 was well dispersed in the iron borate nano-particulate matrix after grinding. The oxidation of benzyl alcohol was investigated using the prepared catalysts. The reaction was carried out in a stirred reactor under reflux using liquid benzyl alcohol in the presence of hydrogen peroxide oxidant, focusing on the conversion and selectivity towards benzaldehyde. Optimization studies were carried out for the solvent type, temperature, reaction time, benzyl alcohol/catalyst ratio, and catalyst composition parameters. It was observed that conversion increased with CeO2 addition up to a certain molar percentage but decreased again on further addition. 34.3% conversion and 81.5% benzaldehyde selectivity were reached after 4 h of reaction at 90 °C in a solvent-free environment with the catalyst containing 5% CeO2. The catalyst was found to be stable when used under these conditions, and there was a slight decrease in its activity after three recycles. [ABSTRACT FROM AUTHOR]

The catalytic behavior of La0.4Sr0.6MnO3 (PM3), La0.8Sr0.2MnO3 (PM2), and LaMnO3 (PM1) has been studied in the oxidation of natural terpenes (α-pinene, β-pinene, limonene, and valencene) in water. To find the best catalytic performance, several parameters were investigated such as the catalyst amount, the nature of the oxidant agent, the oxidant ratio, the temperature, the reaction time, and the nature of the solvent with the α-pinene as the model substrate. PM3 catalyst exhibited the best activity in the oxidation reaction using hydrogen peroxide as an oxidant agent giving a good yield towards verbenone with 50%. The recyclability of the catalyst performances showed remarkable stability after four cycles. Moreover, the photocatalytic mechanism of α-pinene using La1−xSrxMnO3 catalyst was performed through the density functional theory method, and the possible attack site for the photocatalytic reaction between α-pinene and the hydroperoxyl radical (⋅OOH) was predicted using the condensed Fukui function and obtained findings are in good agreement with the experimental results. [ABSTRACT FROM AUTHOR]

Four tridentate ligands L1-L4, namely N,N-bis((3,5-dimethyl-1H-pyrazol-1-yl)methyl) pyridin-2-amine: L1, 5-chloro-N,N-bis((3,5-dimethyl-1H-pyrazol-1-yl)methyl) pyridin-2-amine:L2, N,N-bis((3,5-dimethyl-1H-pyrazol-1-yl)methyl)thiazol-2-amine:L3 and N,N-bis((3,5-dimethyl-1H-pyrazol-1-yl)methyl)-6-methylpyridin-2-amine: L4 were synthesized, characterized (by13C NMR, 1H NMR and mass spectroscopy) and employed for the synthesis of copper(II) complexes in situ. These ligands contain three sp2 nitrogen atoms, two pyrazole nitrogen and one pyridine nitrogen, capable of coordinating with copper (II). Then the catalytic properties of certain complexes formed in situ were evaluated to catalyze the oxidation of catechol to o-quinone. Among these complexes, the L1/Cu(CH3COO)2 complex which showed good catalytic activity of the combination 1:1 ligand/metal in THF for this reaction, with a reaction rate of oxidation of catechol to o-quinone equal to 26.37 μmol L−1 min−1. [ABSTRACT FROM AUTHOR]

The kinetics of oxidation of ammonium sulfite from flue gas desulfurization by ammonia process was studied by changing initial ammonium sulfite concentration, pH, air flow rate, temperature, and concentration of ammonium sulfate in a bubble reactor. The experimental results show that the oxidation rate of ammonium sulfite decreased with the increase of pH but increased with the increase of temperature and airflow rate when the concentration of ammonium sulfate is 0.15 mol/L, temperature of 25–60°C, and an airflow rate of 150–400 L/h. When the concentration of ammonium sulfate increases from 0.2 to 1.0 mol/L, the oxidation rate of ammonium sulfite decreases. At pH 5.0, the activation energy of the apparent oxidation is 26.40 kJ/mol. A kinetics model containing SO32−, SO4, and O2 is used to simulate the oxidation of ammonium sulfate. The results can provide a theoretical basis for the uncatalyzed oxidation of ammonium sulfite in the process of wet ammonia desulfurization process. [ABSTRACT FROM AUTHOR]

Volatile organic compounds (VOCs) have a wide variety and large emissions. VOCs are precursors of ozone and photochemical smog. Some VOCs, such as benzene, toluene, and xylene (BTX), are carcinogenic, teratogenetic, and mutagenic, which can greatly harm the skin, viscera, and nervous system. Researchers estimated in 2013 that 5.5 million people died from air pollution worldwide, thus becoming a serious threat to our daily lives. In the context of massive VOC emissions, the dramatic decline of the regional air quality, and the frequent occurrence of environmental problems, more attention has been paid to the control of VOCs. Governments have formulated a series of regulations and policies to limit the emissions of man-made VOCs. Under the guidance of strict policies, scholars have conducted extensive research on the governance technology of VOCs. Taking the catalytic oxidation of VOCs as the topic in this study, 4654 papers were processed by the Web of Science database, and the development tendency and research status of the topic were analyzed by way of bibliometrics. Results show that the VOC catalytic oxidation has abundant research depth in the past 25 years. The research prospect is found to be admirable and the number of published papers shows an exponential growth trend. China is the largest contributor of publications in the world, accounting for 34% of the total research. The biggest producing institution and journal are the University of Chinese Academy of Sciences (6.66%) and the Applied Catalysis B-Environmental (11.68%), respectively. Chemistry and Engineering are the most popular subjects. In addition, the hot word analysis in recent years shows that the most popular element in the catalyst is Mn, while toluene is the most common substrate of VOCs in the experiment. At the same time, this paper summarizes common catalyst substances and VOC substrates, which consequently reflects the current main research direction and provides guidance for future research.

A carboxylate bridged dimeric metal–organic framework involving a monocarboxylic acid (phenylpropionic acid) and N-donor ligand (2,2-bipyridine), Cu 2 (μ 2 -η2:η1(ppa) 2 (μ 2 -η1:η1 (ppa)bpy) 2 ]·ClO 4 ·H 2 O, structurally characterized by X-Ray diffraction. The Cu(II)-complex exhibits high activity and selectivity as a catalyst for the oxidation of thymol to thymoquinone without additive in a acetonitrile with TBHP. Under optimised conditions, the maximum conversion of thymol (100 %) was obtained with 100 % selectivity to thymoquinone after 35 min at the thymol to catalyst mole ratio of 267 (TOF = 449 h−1) in acetonitrile at 55 °C. The second reported example of Cu(II)-mediated homogeneous oxidation of thymol in an organic solvent, with the catalyst recycled four times without loss of activity, was also described. [Display omitted] A carboxylate-bridged dinuclear copper(II) complex, [Cu 2 (μ 2 -η2:η1(ppa) 2 (μ 2 -η1:η1 (ppa)bpy) 2 ]·ClO 4 ·H 2 O (ppa (C 9 H 9 OO) = 2-phenyl propionate, bpy = 2,2′-bipyridine), was prepared and its structure was determined by X-ray diffraction analysis. The octacoordinated Cu(II) dimer complex exhibits an asymmetric conformation, with the metal centers linked by two distinct modes of the carboxylate group. These include an asymmetric chelating bridging bidentate involving two ppa ligands and a syn-syn bidentate bridging mode involving one ppa ligand. The complex was employed as a catalyst for the oxidation of thymol, demonstrating a high degree of quantitative conversion and selectivity with TBHP across a range of solvents at moderate temperatures. The homogeneous catalytic system, comprising Cu(II)-2-phenyl propionate-bipyridine, tert -butylhydroperoxide (TBHP) as oxidant, and a polar aprotic solvent (acetonitrile or acetone), demonstrated high turnover numbers (TOF) in the absence of any additives. The impact of temperature, solvent, the ratio of thymol to TBHP, different oxidants and the quantity of catalyst on the catalytic activity and product selectivity was examined. Under optimized conditions, the maximum conversion of thymol (100 %) was obtained with 100 % selectivity to thymoquinone with TBHP after 35 min at the thymol to catalyst mole ratio of 267 (TOF = 449 h−1) in acetonitrile (MeCN) at 55 °C. Based on the available evidence, this activity and selectivity to thymoquinone represent the highest reported level of performance achieved by a homogeneously copper-catalysed process. [ABSTRACT FROM AUTHOR]

Solutizon is an original anti-TB drug that is effective in resisting mycobacteria to other anti-TB drugs, which is obtained by the interaction of thiosemicarbazone 4-aminobenzaldehyde and sodium oxymethylene sulfonate. 4-Aminobenzaldehyde is synthesized by redox conversion of 4-nitrotoluene in the presence of sodium polysulfide. The reaction is carried out in boiling alcohol, and 4-aminobenzaldehyde is separated after steam distillation with a yield of 40–50 %. However, today this method loses its practical, environmental and economic attractiveness, as it has significant disadvantages – low product yield, high reaction temperature (80–120 °C), the formation of sulfur-containing wastewater. Therefore, the development of low-temperature, environmentally friendly methods for obtaining 4-aminobenzaldehyde is an urgent task. The aim of the work is to study the kinetic features and mechanism of the liquid-phase reaction of ozone with 4-aminotoluene to create a new low-temperature, environmentally friendly method for the synthesis of 4-aminobenzaldehyde. Materials and methods. Sigma acetic anhydride of сh.р. qualification was used for the experiments. 4-Aminotoluene company “Sinbias” qualification “сh.р.”; 4-Acetamidotoluene and its derivatives were used chromatographically pure. Acetates of metals of qualification “сh.р.”, potassium bromide of qualification “pharmacopoeial” were used without additional purification. Continuous control of the current ozone concentration and recording the results in the form of a kinetic curve was carried out when passing ozone-containing gas through the container of the spectrophotometer “SF-46 LOMO” at a certain wavelength of a monochromatic light source. The results of the analysis were recorded using the KSP-4 potentiometer included in the spectrophotometer optical density reference circuit. This device automatically compensated the photocurrent by recording its value. The scale KSP-4 was calibrated in units of optical density, and the conversion into absolute ozone concentration was carried out according to the Lambert-Ber equation using molar extinction coefficients. Relative analysis error ≤5 %. At the optical stroke length of the container 10 ÷ 100 mm, the sensitivity of the device was ~10-7mol·l-1 ozone. Results. The kinetic features and mechanism of the liquid-phase reaction of ozone with 4-aminotoluene have been studied. It is shown that the developed catalytic system Mn(II)-KBr-H2SO4-Ac2O significantly increases the depth, rate, and selectivity of oxidation of 4-aminotoluene and the main reaction product is 4-aminobenzaldehyde in the form of the corresponding benzylidenediacetate with a yield of 69.5 %. The active particle responsible for the inclusion of the substrate in the oxidation of the methyl group in the presence of manganese (II) acetate and potassium bromide is manganese bromide ion radical (Mn(II)Br•), which is more active than Mn (III) and therefore more high-speed initiates oxidation by the methyl group. Conclusions. Catalytic systems have been developed that allow the oxidation of ozone to be directed mainly to the methyl group of 4-aminotoluene and to stop the reaction at different oxidation depths. It was found that manganese (II) acetate, which has a relatively low redox potential, in the system Ac2O-ArCH3-H2SO4-O3 at a temperature of 20 °C has a high substrate selectivity in the reactions of formation of 4-aminobenzyl alcohol. Manganese (II) acetate in the presence of potassium bromide forms a manganese bromide complex with increased catalytic activity, which under the same conditions contributes to the predominant production of 4-aminobenzaldehyde.

The effect of the process temperature and the initial concentration of Mg, Ca, Sr, Ba, Zn, Cd, and Hg 2-ethylhexanoates as catalysts on the productivity and selectivity of the oxidation stage of cumene is studied in the technological chain for the production of polymer composites from cumene; "production of phenol by cumene method (stage 1 is cumene oxidation to cumene hydroperoxide, stage 2 is decomposition of cumene hydroperoxide into phenol and acetone) → production of precursors from phenol → production of polymers from precursors → production of composites from polymers". A criterion has been introduced that reflects the productivity of cumene oxidation at the moment of reaching the maximum concentration of cumene hydroperoxide, which takes into account the cumene conversion and selectivity achieved in this case in the shortest possible time using the selectivity comparable with the selectivity of a non-catalytic process. It has been shown that the achievement of the maximum value of this criterion, among all the considered catalysts, is ensured by Mg 2-ethylhexanoate at its relatively low initial concentration (1 mmol/L) under conditions of moderately-high process temperatures (393–413 K). [ABSTRACT FROM AUTHOR]

The CoxOy/AC catalysts were prepared by wet impregnation method for toluene oxidation removal from air. The thermal stability of cobalt nitrate and Co oxide on the activated carbon (AC) support surface was analysed by thermal analysis. The physicochemical properties of the prepared catalysts were characterised by XRD, SEM, H2-TPR, and XPS. AC support with high specific surface area and developed pore structure can promote the dispersion of Co species on its surface to form highly dispersed Co oxide species. The participation of AC supports can promote the partial reduction of Co3O4 species to CoO species to coexist in the prepared CoxOy/AC catalyst. The Co2+/Co3+ ratio was significantly affected by the calcination temperature, and the appropriate Co2+/Co3+ ion pairs in the studied CoxOy/AC catalyst is helpful to the activity of O2 molecules to form reactive oxygen species. The oxygen species composition on the catalyst surface is obviously affected by the calcination temperature, which plays an important role in toluene oxidation reaction. The studied CoxOy/AC catalysts exhibited excellent toluene oxidation removal performances. The conversion of toluene exceeded 97% and 99% at 240°C and 250°C, respectively, and maintained good stability within 700 min. That is to say, the concentration of toluene in the air can be reduced from 10,000 ppm to less than 40 ppm by using the CoxOy/AC catalyst. [ABSTRACT FROM AUTHOR]

Purpose. To investigate the peculiarities of the catalytic action of transition metals in combination with mineral acids for the creation of selective syntheses of oxygen-containing derivatives of methylbenzenes by direct oxidation by ozone in the liquid phase. Methodоlogy. A glass column with a porous membrane was used to disperse the gas to establish the kinetic regularities of the reactions of ozone with 4-hydroxytoluene and its acylated derivative. The kinetic parameters of the reaction were studied in a reactor of the "catalytic duck" type, the shaking of which at a speed of 8 oscillations per second provided the kinetic region of the process. The concentration of ozone in the gas phase and the rate constants of its reactions with arenes were determined using the spectrophotometric method of analysis on the SF-46 spectrophotometer. Quantitative content of the reaction mass was recorded by the method of gas-liquid chromatography on the LHM-8MD chromatograph. The concentration of aliphatic peroxides was determined by the method of iodometric titration. Findings. The catalytic reaction of the oxidation of 4-hydroxytoluene by ozone in the liquid phase was studied. It was established that, in the absence of a catalyst, ozonolysis of the aromatic ring with the formation of aliphatic products takes place, and the total yield of oxidation products by the methyl group of the substrate does not exceed 20.5%. Only after adding to the system catalysts based on transition metal salts, it is possible to increase the selectivity and yield of oxidation products by the methyl group up to 77.2%. Under the conditions of the experiment, the main products are 4-acetoxybenzyl acetate (63.2%) and 4- acetoxybenzylidene diacetate (14.0%). It is shown that in the studied system ArCH3-H2SO4-Ас2О-O3, manganese(II) acetate exhibits the greatest catalytic activity, while cobalt salts have practically no catalytic activity under these conditions. Addition of potassium bromide to the oxidation system increases not only the selectivity of oxidation by the methyl group (94.5%), but also the depth of oxidation. The main reaction product is 4-acetoxybenzylidene diacetate (78.0%), which, if necessary, can be easily hydrolyzed to 4-hydroxybenzaldehyde. Originality. The possibility of direct selective oxidation of 4-hydroxytoluene by ozone is shown. Selected catalytic systems that allow stopping the reaction at the stage of formation of the corresponding aromatic alcohol or aldehyde. It was established that the lack of catalytic activity of cobalt(II) acetate under the conditions of the experiment is related to the high reaction rate of reduction of Co(III) to Co(II) in the As2O-H2SO4-O3 system. Practical value. The obtained experimental data are the basis for the creation of environmentally friendly technologies for the synthesis of aromatic alcohols and aldehydes, which are widely used as active pharmaceutical ingredients for the manufacture of medicinal products. [ABSTRACT FROM AUTHOR]

Oxidized cotton cellulose with COOH contents of 16.0–24.0%, meeting USP requirements, was produced in the HNO3–H3PO4–NaNO2 system. This allowed it to be used as a biodegradable hemostatic agent. The structures of oxidized cotton celluloses were confirmed using IR spectroscopy and elemental analysis and were studied using X-ray diffraction structure analysis. Diffraction patterns of celluloses oxidized for 4–24 h had reflections characteristic of two polymorphic modifications, i.e., cellulose I (characteristic of starting cotton cellulose) and cellulose II. [ABSTRACT FROM AUTHOR]

The CeO2 and Zr-doped CeO2 (Ce1−xZrxO2) catalysts are synthesized by the green synthesis process and tested for soot oxidation activity. The identification of phase, morphology, and soot oxidation is analyzed by XRD (X-ray diffraction), FE-SEM (field emission scanning electron microscopy), and TGA–DSC (thermogravimetric–differential scanning calorimetry), respectively. The proper replacement of Ce with Zr has been identified in XRD. The catalyst showed higher stability at elevated temperatures for soot oxidation after the introduction of Zr into CeO2. It is observed that Zr-doped CeO2 samples show low-temperature soot oxidation reactivity than pure CeO2. Soot oxidation is found between the temperature range of 427–455 °C. The Zr-doped CeO2 catalyst showed higher stability and reactivity than pure CeO2. [ABSTRACT FROM AUTHOR]

Formaldehyde (HCHO) is toxic to the human body and is one of the main threats to the indoor air quality (IAQ). As such, the removal of HCHO is imperative to improving the IAQ, whereby the most useful method to effectively remove HCHO at room temperature is catalytic oxidation. This review discusses catalysts for HCHO room-temperature oxidation, which are categorized according to their preparation methods, i.e., gas-phase reduction and liquid-phase reduction methods. The HCHO oxidation performances, structural features, and reaction mechanisms of the different catalysts are discussed, and directions for future research on catalytic oxidation are reviewed. [Display omitted] [ABSTRACT FROM AUTHOR]

Formaldehyde is an important downstream chemical of syngas. Furniture and household products synthesized from formaldehyde will slowly decompose and release formaldehyde again during use, which seriously affects indoor air quality. In order to solve the indoor formaldehyde pollution problem, this paper took the catalytic oxidation of formaldehyde as the research object; prepared a series of low-cost, acid-treated manganese dioxide nanorod catalysts; and investigated the effect of the acid-treatment conditions on the catalysts' activity. It was found that the MnNR-0.3ac-6h catalyst with 0.3 mol/L sulfuric acid for 6 h had the best activity. The conversion rate of formaldehyde reached 98% at 150 °C and 90% at 25 °C at room temperature. During the reaction time of 144 h, the conversion rate of formaldehyde was about 90%, and the catalyst maintained a high activity. It was found that acid treatment could increase the number of oxygen vacancies on the surface of the catalysts and promote the production of reactive oxygen species. The amount of surface reactive oxygen species of the MnNR-0.3ac-6h catalyst was about 13% higher than that of the catalyst without acid treatment. [ABSTRACT FROM AUTHOR]

N‐Hydroxypthalimide (NHPI) has become a powerful and versatile organocatalyst, it has been known to catalyze various free‐radical processes leading to the wide range of organic transformations. Primarily, phthalimido‐N‐oxyl (PINO) radical formed from NHPI is highly efficient abstraction species for carrying out radical chain reactions. In this review, we have discussed about the most important and successful reactions from last six years, with their plausible reaction mechanisms. This review broadly covers the type of bond formation such as carbon‐carbon, carbon‐oxygen and carbon‐nitrogen bond formations. We have also highlighted various types of reaction strategies where in combination with divergent reagent systems it helps to construct different types of molecules which further find applications in the synthesis of complex set of biologically active molecule. NHPI catalyzed oxidation reactions of different class of organic compounds are also reviewed. [ABSTRACT FROM AUTHOR]

The influence of the support‐oxygen groups and Pt particle size on the catalytic performance of Pt/AC for the aerobic oxidation of α‐D‐glucose to gluconic acid (glycolate) was studied. Surface‐oxygen groups were introduced by treating the activated carbon support with diluted HNO3 without significantly affecting the support porosity. The platinum particle size could be decreased on both the treated and untreated support by adding an additional calcination step to the synthesis. The presence of oxygen‐containing groups is shown to be highly beneficial (∼4 fold increase in the turnover frequency) only for the smallest Pt particle size (1.8–2.5 nm, determined by TEM). For the catalyst with the larger Pt size (3.4–3.6 nm), the presence of additional oxygen‐contacting groups does not significantly enhance the activity. Since the size of the smaller Pt particles is close to the product/substrate molecular diameter (glucose/gluconic acid, ∼0.9 nm) the observed effect can be attributed to the effective repulsion by the negatively charged oxygen groups in close proximity to the glycolate reaction product. The increase in activity originates from the resulting enhanced desorption of glycolate by alleviating the product inhibition presence due to the strong interaction of glycolate with Pt. [ABSTRACT FROM AUTHOR]

Research into the incorporation of cerium into a diverse range of catalyst systems for a wide spectrum of process chemistries has expanded rapidly. This has been evidenced since about 1980 in the increasing number of both scientific research journals and patent publications that address the application of cerium as a component of a multi-metal oxide system and as a support material for metal catalysts. This review chronicles both the applied and fundamental research into cerium-containing oxide catalysts where cerium's redox activity confers enhanced and new catalytic functionality. Application areas of cerium-containing catalysts include selective oxidation, combustion, NOx remediation, and the production of sustainable chemicals and materials via bio-based feedstocks, among others. The newfound interest in cerium-containing catalysts stems from the benefits achieved by cerium's inclusion, which include selectivity, activity, and stability. These benefits arise because of cerium's unique combination of chemical and thermal stability, its redox active properties, its ability to stabilize defect structures in multicomponent oxides, and its propensity to stabilize catalytically optimal oxidation states of other multivalent elements. This review surveys the origins and some of the current directions in the research and application of cerium oxide-based catalysts. [ABSTRACT FROM AUTHOR]

Oxidation of aldehydes is one of the most important reactions in organic synthesis. This study aims to construct a novel catalyst with high activity for aldehyde oxidation. To achieve this purpose, the magnetic core-shell Fe3O4@Co(x)-ZIF composites were constructed and used for isobutyraldehyde oxidation to isobutyric acid. The isobutyric acid yield when used Fe3O4@Co(x)-ZIF as the catalyst is ranged in 92.5–93.6%. Meanwhile, the Fe3O4@Co(2)-ZIF catalyst prepared with the Co(NO3)2⋅6H2O at an amount of 0.2 mol showed the highest isobutyric acid yield of 93.6% and an isobutyric acid selectivity of 97.6%. In mechanism, we proposed that in Fe3O4@Co(x)-ZIF composites, the Fe3O4 core accelerates the charge transfer and promotes the cycling of Co2+ to Co3+, while the ZIF-67 shell provides a high surface area and abundant ordered Co2+ ion active sites. Therefore, the synergistic effect of the Fe3O4 core and ZIF-67 shell exhibits an excellent oxidation performance. [ABSTRACT FROM AUTHOR]

This study aims to advance the knowledge of using carbon materials as catalysts in the oxidation of chalcopyrite. For this, two different materials (a commercial activated carbon (CC) and commercial biochar (BC)) were added to chalcopyrite ore (CPY) at three weight ratios (1:1, 1:0.5, and 1:0.25). Mixtures were treated with sulfuric/ferric solution for 96 h at 90 °C. Experimental results showed that extraction of copper from CPY was around 36%, increasing to higher than 90% with the addition of CC or BC at the proper ratio. The best result (99.1% Cu extraction) was obtained using a 1:1 ratio of CPY:CC. Analysis of solid residues shows that CC, with a high surface area, adsorbs sulfur onto its surface, limiting elemental sulfur formation. Additionally, the treatment of CPY in the CC's presence transforms the chalcopyrite into CuS. Sulfur adsorption or CuS formation was not observed after the leaching of chalcopyrite with BC. However, the addition of BC to CPY at a ratio of 1:0.25 also increased the extraction of copper to 91.1%. Two carbon materials were oxidized after treatment with a sulfuric/ferric solution, and BC probably displayed catalytic properties in the leaching medium. [ABSTRACT FROM AUTHOR]

The Pt–SnOx, Pd–SnOx, and Au–SnOx composite catalysts were synthesized by pulsed laser ablation. The catalyst testing in the CO + O2 reaction showed that the action of the reaction medium can induce both partial deactivation (Pt–SnOx) and activation (Au–SnOx) of the catalysts. The Pd–SnOx catalyst has a high activity even in the initial state, and the effect of the reaction medium is slight. It was shown that gold and platinum mainly exist in the metallic state, while palladium exists as PdO nanoparticles. Electron transfer between the active component and support particles was detected for the Pt–SnOx and Au–SnOx catalysts. Electron donation effect from the support, enhanced by the action of the reaction medium, was found for Au–SnOx. This effect was assumed to determine the low-temperature activity of the catalyst towards the CO oxidation. [ABSTRACT FROM AUTHOR]

CuCe mixed oxide is one of the most studied catalytic systems for preferential CO oxidation (CO-PrOx) for the purification of hydrogen-rich gas stream. In this study, a series of ceria supports were prepared via a citrates-hydrothermal route by altering the synthesis parameters (concentration and temperature). The resulting supports were used for the preparation of CuCe mixed-oxide catalysts via wet impregnation. Various physicochemical techniques were utilized for the characterization of the resulting materials, whereas the CuCe oxide catalysts were assessed in CO-PrOx reaction. Through the proper modification of the hydrothermal parameters, CeO2 supports with tunable properties can be formed, thus targeting the formation of highly active and selective catalysts. The nature of the reduced copper species and the optimum content in oxygen vacancies seems to be the key factors behind the remarkable catalytic performance of a CO-PrOx reaction. [ABSTRACT FROM AUTHOR]

Nickel-cobalt spinel catalyst (NCO) is a promising catalyst for air oxidation of humic acid, which is a typical natural refractory organic matter and a precursor of toxic disinfection by-products. In this study, reductive etchers, NaBH4 or Na2SO3, were used to adjust the NCO surface structure to increase the performance. The modified catalyst (NCO-R) was characterized, and the relationship between its intrinsic properties and catalytic paths was discovered. The results of O2-temperature programmed desorption, NH3-temperature programmed desorption, and X-ray photoelectron spectroscopy (XPS) demonstrated that reductant etching introduced oxygen vacancies to the surface of NCO and increased active surface oxygen species and surface acidity. In addition, the modification did not change the raw hollow sphere structure of NCO. The crystallinity and specific surface area of NCO-R increased, and average pore size of NCO-R decreased. XPS results showed that the ratio of Co3+/Co2+ in NCO-R decreased compared with NCO, while the ratio of Ni3+/Ni2+ increased. The results of H2-temperature programmed reduction showed that the H2 reduction ability of NCO-R was stronger. Due to these changes in chemical and physical properties, NCO-R exhibited much better catalytic performance than NCO. In the catalytic air oxidation of humic acid at 25 °C, the total organic carbon (TOC) removal rate increased significantly from 44.4% using NCO to 77.0% using NCO-R. TOC concentration of humic acid decreased by 90.0% after 12 h in the catalytic air oxidation using NCO-R at 90 °C. [ABSTRACT FROM AUTHOR]

Nowadays, with the importance of energy problems, alloyed palladium‐based electrocatalysts in low‐dimension have become more and more popular in electrocatalysis. Here Pd−Pb nanowire networks (NNWs) were synthesized hydrothermally with different Pd/Pb molar ratios from 8 : 1 to 3 : 1 and they exhibited excellent electrochemical performance toward ethanol oxidation reaction (EOR). Pd6Pb1 NNW presented the network structure along with the smallest diameter and exhibited a high catalytic activity, excellent stability and great toxicity resistance toward EOR in alkaline conditions. The catalytic current density of the Pd6Pb1 NNW for EOR under alkaline conditions was 2344 mA mg−1, while 2174, 1936 and 1728 mA mg−1 for Pd8Pb1, Pd4Pb1 and Pd3Pb1 NNWs, respectively. It was worth mentioning that Pd6Pb1 NNW had a low activity loss and ended with 92.9% of its own maximum current density after 300 cycling, much better than that of commercial Pd/C. The positive correlation effects of catalytic temperatures and concentrations of KOH and/or ethanol concentrations for Pd−Pb NNWs were observed and discussed based on the electrochemical measurements. [ABSTRACT FROM AUTHOR]

In this study ceramic supported noble metal-free catalysts promoting the oxidation of CO were examined. In the course of our work several non-noble metal containing catalysts were prepared with different metal content by the well-known wet impregnation method and their catalytic activities were analyzed by gas chromatography (GC) experiments in CO oxidation reaction. In addition to GC measurements, X-ray diffraction, scanning electron microscopy, BET and X-ray photoelectron spectroscopy tests were also performed on our samples. During our work we found that cobalt-loaded silica-alumina-based ceramic supported catalyst proved to be the best in CO oxidation due to the high activity and durability with comparable activity with Pt-loaded counterpart. [ABSTRACT FROM AUTHOR]