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Showing papers on "Partial oxidation published in 2013"


Journal ArticleDOI
TL;DR: Mixed-valent amorphous MnOx catalysts suitable for photochemical and electrochemical water oxidation are prepared by treatment of nanostructured catalytically inactive MnO precursors with (NH4)2Ce(NO3)6 solution for 15 min under vigorous stirring as discussed by the authors.
Abstract: Mixed-valent amorphous MnOx catalysts suitable for photochemical and electrochemical water oxidation are prepared by treatment of nanostructured catalytically inactive MnO precursors with (NH4)2Ce(NO3)6 solution for 15 min under vigorous stirring.

261 citations


Journal ArticleDOI
TL;DR: In this paper, a review of commonly used Cu-based catalysts including their kinetic, compositional, and morphological characteristics in methanol reforming reactions is presented, focusing on the commonly reported surface intermediate species, which are methoxy, formaldehyde, dioxymethylene, formate and methyl formate.

213 citations


Journal ArticleDOI
TL;DR: In this article, the methanation of CO and CO2 present in coke oven gas was performed in a fixed-bed catalytic reactor at a reaction temperature between 200 and 400 °C.
Abstract: The methanation of CO and CO2 present in coke oven gas was performed in a fixed-bed catalytic reactor at a reaction temperature between 200 and 400 °C. Different support materials, including SiO2, ...

169 citations


Journal ArticleDOI
Fang He1, Xinai Li1, Kun Zhao1, Zhen Huang1, Guoqiang Wei1, Haibin Li1 
01 Jun 2013-Fuel
TL;DR: In this paper, the synthesis of perovskite-type oxides was investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) surface area, temperature-programmed reduction (TPR), and Fourier transformed infrared spectroscopy (FTIR).

149 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of nickel content on NiO-MgO-ZrO 2 catalysts was investigated and the results showed that high nickel content favored the formation of large Ni° particles during the reforming reaction, thus lowering the catalytic performance.

122 citations


Journal ArticleDOI
TL;DR: In this article, the effect of SO2 on Hg0 oxidation over a highly active CeO2-TiO2 catalyst was investigated, and the results suggest a balance point for SO2 concentration, where the promotional effect on HO oxidation by SO3 originated from SO2 and subsequent HO oxidation via the Langmuir-Hinshelwood mechanism.

121 citations


Journal ArticleDOI
TL;DR: In this article, the authors reviewed the technological features and challenges of autothermal reforming (ATR) of heavy hydrocarbon fuels for producing hydrogen and syngas onboard to supply fuels to fuel cells for auxiliary power units.

120 citations


Journal ArticleDOI
Zhiwei Ge1, Simao Guo1, Liejin Guo1, Changqing Cao1, Xiaohui Su1, Hui Jin1 
TL;DR: In this paper, hydrogen production by non-catalytic partial oxidation of coal was systematically investigated in supercritical water (SCW) with quartz batch reactors for the first time, and the influences of the main operating parameters including residence time, temperature, oxidant equivalent ratio (ER) and feed concentration on the gasification characteristics of coal were investigated.

108 citations


Journal ArticleDOI
TL;DR: The results highlighted the important impact of size-induced oxidation state of Pt nanoparticles on catalytic selectivity as well as activity in gas-phase methanol oxidation reactions.
Abstract: Pt nanoparticles with various sizes of 1, 2, 4, and 6 nm were synthesized and studied as catalysts for gas-phase methanol oxidation reaction toward formaldehyde and carbon dioxide under ambient pressure (10 Torr of methanol, 50 Torr of oxygen, and 710 Torr of helium) at a low temperature of 60 °C. While the 2, 4, and 6 nm nanoparticles exhibited similar catalytic activity and selectivity, the 1 nm nanoparticles showed a significantly higher selectivity toward partial oxidation of methanol to formaldehyde, but a lower total turnover frequency. The observed size effect in catalysis was correlated to the size-dependent structure and oxidation state of the Pt nanoparticles. X-ray photoelectron spectroscopy and infrared vibrational spectroscopy using adsorbed CO as molecular probes revealed that the 1 nm nanoparticles were predominantly oxidized while the 2, 4, and 6 nm nanoparticles were largely metallic. Transmission electron microscopy imaging witnessed the transition from crystalline to quasicrystalline structure as the size of the Pt nanoparticles was reduced to 1 nm. The results highlighted the important impact of size-induced oxidation state of Pt nanoparticles on catalytic selectivity as well as activity in gas-phase methanol oxidation reactions.

99 citations


Journal ArticleDOI
TL;DR: Au supported on γ-Al2O3 prepared by deposition-precipitation (DP) using urea is found to be a highly active catalyst for the total oxidation of HCHO at room temperature under humid air, without the need for a reducible oxide as support as discussed by the authors.

96 citations


Journal ArticleDOI
TL;DR: In this paper, the authors investigated the catalytic activity and selectivity of CeO2-based catalysts in the production of H2 and CO through MPO using X-ray photoelectron spectroscopy (AP-XPS).
Abstract: Methane partial oxidation (MPO) chemically transforms natural gas into syngas for the production of gasoline. CeO2 doped with transition-metal ions is one type of catalyst active for MPO. A fundamental understanding of MPO on this type of catalyst is important for the development of catalysts with high activity and selectivity for this process. CeO2-based catalysts, including Pd-CeO2-air, Pd-CeO2-H2, Pt-CeO2-air, Pt-CeO2-H2, Rh-CeO2-air, and Rh-CeO2-H2, were synthesized through doping noble-metal ions in the synthesis of CeO2 nanoparticles. The catalytic activity and selectivity in the production of H2 and CO through MPO on these ceria-based catalysts as well as their surface chemistries during catalysis were investigated. They exhibit quite different catalytic performances in MPO under identical catalytic conditions. In situ studies of their surface chemistries during catalysis, using ambient-pressure X-ray photoelectron spectroscopy (AP–XPS), revealed quite different surface chemistries during catalysis...

Journal ArticleDOI
TL;DR: In this paper, the authors used Raman spectroscopy, electron microscopy, and microkinetic modeling to study the catalytic partial oxidation of methane on Pt. The measured species profiles through Pt coated foam catalysts exhibit a two-zone structure: an abrupt change in reaction rates separates the fast exothermic oxidation chemistry at the entrance of the reactor from the slow end-othermic reforming chemistry.

Journal ArticleDOI
TL;DR: A series of nickel-based catalysts supported on silica (Ni/SiO 2 ) with different loading of Ce/Ni (molar ratio ranging from 0.17 to 0.84) were prepared using conventional co-impregnation method and were applied to synthesis gas production in the combination of CO 2 reforming with partial oxidation of methane as mentioned in this paper.

Journal ArticleDOI
TL;DR: In this paper, a new concept for syngas production is presented with the use of redox stable lanthanum chromite and Lanthanum ferrite perovskites with A-site doping of Ba, Ca, Mg and Sr as the pure atomic oxygen source for the catalytic partial oxidation of methane.

Journal ArticleDOI
TL;DR: In this paper, the influence of an electric field on an ultrathin FeCo film was investigated by x-ray absorption spectroscopy and magnetic circular dichroism, and the results showed that electrochemical phenomena may influence the magnetism at a ferromagnet/insulator interface.
Abstract: The influence of an electric field on an ultrathin FeCo film was investigated by x-ray absorption spectroscopy and magnetic circular dichroism. Measurements were done on sub-millimeter sized pillars, with partial fluorescence yield detection. Fe L2,3 absorption spectra revealed that partial oxidation of Fe occurred during the microfabrication. The oxidation state could be reversibly controlled by an electric field, which also induced variations of the dichroic signal. These results show that electrochemical phenomena may influence the magnetism at a ferromagnet/insulator interface.

Journal ArticleDOI
TL;DR: It is demonstrated that ethene is also formed and can be subsequently oxidized, and the mechanism of ethane oxidation involves carbon-based radicals, which lead to the high conversions the authors observe.
Abstract: Iron and copper containing ZSM-5 catalysts are effective for the partial oxidation of ethane with hydrogen peroxide giving combined oxygenate selectivities and productivities of up to 95.2% and 65 mol kgcat–1 h–1, respectively. High conversion of ethane (ca. 56%) to acetic acid (ca. 70% selectivity) can be observed. Detailed studies of this catalytic system reveal a complex reaction network in which the oxidation of ethane gives a range of C2 oxygenates, with sequential C–C bond cleavage generating C1 products. We demonstrate that ethene is also formed and can be subsequently oxidized. Ethanol can be directly produced from ethane, and does not originate from the decomposition of its corresponding alkylperoxy species, ethyl hydroperoxide. In contrast to our previously proposed mechanism for methane oxidation over similar zeolite catalysts, the mechanism of ethane oxidation involves carbon-based radicals, which lead to the high conversions we observe.

Journal ArticleDOI
TL;DR: In this paper, a comparison of catalytic systems employed in the production of syngas by the catalytic partial oxidation of methane, as well as experimental evidences on the reaction mechanisms are examined.
Abstract: Natural gas is catalytically converted into several bulk chemicals such as ammonia, methanol, dimethyl ether, and synthetic liquid fuels by Fischer-Tropsch synthesis and similar processes. The main step in the conversion of natural gas to these products is the production of synthesis gas with the desired composition ranging from H2/CO = 3:1 used for the production of ammonia to the 1:1 mixture preferred for production of dimethyl ether. Catalysts and catalytic processes are important in the production of synthesis gas from natural gas. In this work, relevant catalytic systems employed recently in the production of syngas by the catalytic partial oxidation of methane, as well as experimental evidences on the reaction mechanisms are examined. Differences in methane dissociation, binding site preferences, stability of OH surface species, surface residence times of active species and contributions from lattice oxygen atoms and support species are considered. The methane dissociation requires reduced metal sites, but at elevated temperatures oxides of active species may be reduced by direct interaction with methane or from the reaction with H2 and CO (or C). The comparison of elementary reaction steps on Pt and Rh illustrates the fact that a key factor to produce hydrogen as primary product is a high activation energy barrier to the formation of OH. Another essential property for the formation of H2 and CO as primary products is a low surface coverage of intermediates, such that the probability of O-H, OH-H and CO-O interactions is reduced.

Journal ArticleDOI
TL;DR: In this paper, high energy resolved fluorescence detected X-ray absorption spectroscopy (HERFD XAS) and extended Xray absorption fine structure (EXAFS) were explored to monitor the structure of the Cu atoms in Cu-MOR under the different gas feeds.

Journal ArticleDOI
01 Oct 2013-Fuel
TL;DR: In this article, the authors investigated to what extent the partial oxidation process of the pyrolysis gas from the first stage is involved in direct and in-direct tar destruction and conversion.

Journal ArticleDOI
TL;DR: In this article, the solar photo-Fenton has been demonstrated to be an effective process for the purification of winery effluents, yielding after 120min of treatment, COD, DOC and color removal of 70.3%, 53.7% and 75.2% respectively.
Abstract: This work examined the solar-photo Fenton oxidation against the bioresistant fractions of winery wastewater. Winery effluents already treated by a membrane bioreactor (MBR) were subjected to further purification by solar photo-Fenton oxidation process (hv/Fe2+/H2O2). The effect of various operating variables, such as the catalyst and oxidant concentration, as well as temperature and solar irradiation on the abatement of chemical oxygen demand (COD), dissolved organic carbon (DOC), color, toxicity and phytotoxicity has been assessed. Optimum Fe2+ and H2O2 concentrations were found to be 3 mg L−1 and 250 mg L−1, respectively. Solar photo-Fenton has been demonstrated to be an effective process for the purification of winery effluents, yielding after 120 min of treatment, COD, DOC and color removal of 70 ± 3.3%, 53 ± 3.7% and 75 ± 2.2%, respectively. The residual COD and DOC values after the end of the solar treatment were 33 mg L−1 and 14.1 mg L−1, respectively. In the various operating conditions studied, the extent of mineralization (assessed by DOC) was lower than the COD decrease, implying that partial oxidation reactions of the organic content prevailed over total oxidation to CO2 and water. Moreover, the process efficiency was found to increase with temperature up to a point (∼70% at 25 °C), and then reach a plateau with a small increase by further increasing the temperature to 45 °C. Finally, the toxic and the phytotoxic compounds still present in the effluent after the biological treatment were reduced or even eliminated through solar photo-Fenton oxidation.

Journal ArticleDOI
01 Nov 2013-Fuel
TL;DR: In this article, a co-precipitation method with the addition of pluronic P123 triblock copolymer as surfactant was used to synthesize a high specific surface area Ni/MgAl 2 O 4 catalyst for combined and partial oxidation of methane.

Journal ArticleDOI
TL;DR: Aerobic Baeyer-Villiger oxidation of ketones to corresponding esters was performed using metal-free carbon as a solid catalyst and benzaldehyde as the sacrificing agent.
Abstract: Aerobic Baeyer–Villiger oxidation of ketones to corresponding esters was performed using metal-free carbon as a solid catalyst and benzaldehyde as the sacrificing agent. Several carbon materials were tested for the oxidation of cyclohexanone to e-caprolactone, and it was found that Ketjen Black showed the highest catalytic activity, over 90% of e-caprolactone yield at 50 °C. A catalyst recycling test suggests that the catalyst has high durability under the reaction condition of oxygen atmosphere at 50 °C. Mechanistic study suggests that peracid species produced by a series of chain propagation reactions is the key intermediate, and the carbon catalyst contributes to high aldehyde efficiency by buffering the radical species, which are essential for the chain propagation reactions.

Journal ArticleDOI
TL;DR: In this paper, the influence of the metal, of the support, and of metal-support interactions in Au/ZnO and Au/TiO 2 catalysts was investigated under continuous flow conditions in fixed-bed reactors.

Journal ArticleDOI
TL;DR: In this paper, three known types of ethanol reforming processes, ethanol steam reforming (ESR), partial oxidation (POX) and auto-thermal reforming (ATR), are investigated.

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the development of a CeO2-promoted Fe2O3-hematite oxygen carrier suitable for the methane CLC process, which is a promising technology for fossil fuel combustion that produces sequestration-ready CO2 stream.
Abstract: Chemical looping combustion (CLC) is a promising technology for fossil fuel combustion that produces sequestration-ready CO2 stream, reducing the energy penalty of CO2 separation from flue gases. An effective oxygen carrier for CLC will readily react with the fuel gas and will be reoxidized upon contact with oxygen. This study investigated the development of a CeO2-promoted Fe2O3–hematite oxygen carrier suitable for the methane CLC process. Composition of CeO2 is between 5 and 25 wt % and is lower than what is generally used for supports in Fe2O3 carrier preparations. The incorporation of CeO2 to the natural ore hematite strongly modifies the reduction behavior in comparison to that of CeO2 and hematite alone. Temperature-programmed reaction studies revealed that the addition of even 5 wt % CeO2 enhances the reaction capacity of the Fe2O3 oxygen carrier by promoting the decomposition and partial oxidation of methane. Fixed-bed reactor data showed that the 5 wt % cerium oxides with 95 wt % iron oxide produ...

Journal ArticleDOI
Fang He1, Kun Zhao1, Zhen Huang1, Xin'ai Li1, Guoqiang Wei1, Li Haibin1 
TL;DR: In this article, a 3D-ordered macroporous (3DOM) LaFeO 3 perovskite-type oxides were synthesized using a polystyrene colloidal crystal templating method.

Journal ArticleDOI
TL;DR: In this article, the catalytic partial oxidation (CPOX) of ethanol was studied over rhodium/alumina-coated monoliths, yielding spatially resolved temperature and concentration profiles.
Abstract: The catalytic partial oxidation (CPOX) of ethanol was studied over rhodium/alumina-coated monoliths. An in situ sampling technique was used for ethanol CPOX, yielding spatially resolved temperature and concentration profiles. Molar C/O ratios from 0.65 to 0.85 were studied. Catalytic and blank experiments were both performed. The investigations clearly showed two zones inside the catalytic channel, an oxy-reforming zone as long as oxygen is present, with total oxidation and steam reforming as prevalent reactions, and a reforming zone, with steam reforming as the dominating reaction. Moreover, homogeneous gas-phase reactions, leading mainly to acetaldehyde and water, were observed in front of the catalyst. This was confirmed by blank experiments, which showed that homogeneous conversion of ethanol by oxidative dehydrogenation may occur in absence of a catalyst at temperatures higher than 640 K. Additionally, axial profiles were collected at a fixed C/O ratio in three catalytic channels, which were differently located across the monolith. A radial heat loss from the center to the outer channels of the monolith was observed, which led to variations in the axial concentration profiles across the honeycomb.

Journal ArticleDOI
TL;DR: C-H activation of inert hydrocarbons: New cobalt, nickel and copper complexes with the tripodal 4N ligand Me6TREN (tris[2-(dimethylamino)ethyl]amine and related compounds are tested as homogeneous catalysts for the partial oxidation of cyclohexane and adamantane in the presence of the sacrificial oxidant m-chloroperbenzoic acid.

Journal ArticleDOI
TL;DR: In this paper, a low-impurity product from glycerol purification unit of a biodiesel manufacturing called yellow glycerols, was shown to be an alternative raw material for H2 generation via oxidative steam reforming reaction over Ni/CeZrO2/Al2O3 catalyst.

Journal ArticleDOI
TL;DR: In this paper, powder X-ray diffraction (PXRD), Xray photoelectron spectra (XPS), and temperature-programmed reduction (TPR) were used as catalysts for the autothermal steam reforming of ethanol.
Abstract: Pyrochlore phases solid solutions, La 2 Ce 2− x Ru x O 7 ( x = 0–0.35) were prepared with a sol–gel process and used as catalysts for the autothermal steam reforming of ethanol. The samples as prepared were characterized with powder X-ray diffraction (PXRD), X-ray photoelectron spectra (XPS), and temperature-programmed reduction (TPR). The XPS and TPR spectra revealed the effect of doped Ru n + to oxidation states of La and Ce sites. The low temperature reduction ability and relative concentration of Ce 4+ ions are increased as the cell-dimension decreased. Tests of catalytic activity showed that the reforming performance of La 2 Ce 2− x Ru x O 7 catalysts was affected by the Ru/Ce loading ratio. For all catalysts, partial oxidation was favored at a large C/O composition; incomplete ethanol conversion was observed for C/O ≥ 0.7. The optimized catalyst was La 2 Ce 1.8 Ru 0.2 O 7 with hydrogen production rate ( r H 2 ) 2.01 × 10 −3 mol s −1 g cat −1 (autothermal temperature ∼600 °C and 97% ethanol conversion at C/O = 0.6). The catalyst exhibited stable r H 2 over 26 h of the reaction with ethanol conversion >95%. r H 2 of the catalyst gradually decreased thereafter because LaAlO 3 started to formed and affected catalytic process. For the catalyst, the Ru ions remained well dispersed before and after the AESR reaction.