Modulating the CO methanation activity of Ni catalyst by nitrogen doped carbon

Nitrogen doping has been proved to be an effective way to modify the properties of graphene and other carbon materials. Herein, we explore a composite with nitrogen doped carbon overlayers wrapping Si C substrate as a support for Ni（Ni/CN-Si C） and evaluate its effects on the methanation activity. The results show that both the activity and stability of Ni are enhanced. Characterization with STEM, XRD, XPS, Raman and H2-TPR indicates that nitrogen doping generates more defects in the carbon overlayers, which benefit the dispersion of Ni. Furthermore, the reduction of Ni is facilitated.

Improved activity of Ni/MgAl_2O_4 for CO_2 methanation by the plasma decomposition

CO2 methanation has been a hot topic because of its important application in the spacecraft and potential utilization of carbon dioxide. Nickel catalyst is active for this reaction. However, its activity still needs to be improved. Dielectric barrier discharge （DBD） plasma, initiated at ambient condition and operated at -150 ℃, has been employed in this work for decomposition of nickel precursor to prepare Ni/MgAl2O4. The plasma decomposition results in high dispersion, unique structure, enhanced reducibility of Ni particles and promoted catalyst-support interaction. An improved activity of CO2 methanation with a higher yield of methane has been achieved over the plasma decomposed catalyst, compared to the catalyst prepared thermally. For example, the methane yield of the plasma prepared catalyst is 71.8% at 300 ℃ but it is 62.9% over the thermal prepared catalyst. The catalyst characterization confirmed that CO2 methanation over the DBD plasma prepared catalyst follows pathway of CO methanation.

Development of Cu foam-based Ni catalyst for solar thermal reforming of methane with carbon dioxide

Using solar energy to produce syngas via the endothermic reforming of methane has been extensively inves- tigated at the laboratory- and pilot plant-scales as a promising method of storing solar energy. One of the challenges to scaling up this process in a tubular reformer is to improve the reactor＇s performance, which is limited by mass and heat transfer issues. High thermal conductivity Cu foam was therefore used as a sub-strate to improve the catalyst＇s thermal conductivity during solar reforming. We also developed a method to coat the foam with the catalytically active component NiMg3AlOx. The Cu foam-based NiMg3AlOx performs better than catalysts supported on SiSiC foam, which is currently used as a substrate for solar-reforming cat- alysts, at high gas hourly space velocity （≥400,000 mL/（g.h）） or at low reaction temperatures （≤ 720 ℃）. The presence of a γ-Al2O3 intermediate layer improves the adhesion between the catalyst and substrate as well as the catalytic activity.

Synergism of Plasma and Catalyst on the Dehydrogenative Coupling of Methane

At atmospheric pressure and ambient temperature, pulse corona induced plasma was used as a new method for dehydrogenative coupling of methane. The synergism of plasma and catalyst on dehydrogenative coupling of methane was investigated. Experimental results have revealed that the synergism does exist, when positive corona within a suitable power range and an intermediate pulse repetition frequency (PRF) for a loaded 7-Mn2O3/7-A12O3 catalyst were chosen. In respect to the mechanism approach, a tentative model for general pathway was proposed to explain the role of plasma and catalyst partaking in the process of methane decomposition and C2 products formation.

METHANE OXIDATIVE COUPLING OVER METAL OXYFLUORIDE CATALYSTS

The MOC reaction over ZrO_2/LaF_3, CeO_2/LaF_3 and ThO_2/LaF_3 catalysts indicated that these catalysts had high activity and high C_2 selectivity at low temperature. In the temperature range 480℃ to 650℃. The methane conversion was 24. 4% to 30. 8% and the C_2 selectivity was 40. 0% to 55. 4%. The XRD characterization of the catalysts indicated that O^2. and F exchang happened and LaOF was formed.

Formation of Methane and Ethylene in Methanol Conversion over HZSM-5 Catalyst

Primary formation of methane and secondary formation of ethylene in methanol conversion are evidenced by temperature-programmed-surface- reaction of adsorbed methanol on HZSM-5 catalyst.A reaction mechanism accounts for the observed results is described.

Nanostructured perovskite oxides as promising substitutes of noble metals catalysts for catalytic combustion of methane

Heterogeneous catalytic combustion provides a feasible technique for high efficient methane utilization.Perovskites ABO_3-type materials have received renewed attention as a potential alternative for noble metals supported catalysts in catalytic methane combustion due to excellent hydrothermal stability and sulfur resistance. Recently, the emergence of nanostructured perovskite oxides（such as threedimensional ordered nanostructure, nano-array structure） with outstanding catalytic activity has further driven methane catalytic combustion research into spotlight. In this review, we summarize the recent development of nanostructured perovskite oxide catalysts for methane combustion, and shed some light on the rational design of high efficient nanostructured perovskite catalysts via lattice oxygen activation,lattice oxygen mobility and materials morphology engineering. The emergent issues needed to be addressed on perovskite catalysts were also proposed.

Effects of Ce on catalytic combustion of methane over Pd-Pt/Al_2O_3 catalyst

Activity and stability of 1%Pd-0.2%Pt/Al2O3 and 1%Pd-0.2%Pt/0.6%Ce/Al2O3 catalysts prepared by impregnation method for catalytic combustion of methane in air were investigated. The catalysts before and after reaction were characterized by BET, CO chemisorption, XRD and XPS techniques. Results showed that the presence of Ce significantly increased the activity and thermal stability of the Pd-Pt/Al2O3 catalyst towards methane combustion, which could be attributed to more highly-dispersed active PdO particles over the Pd-Pt/Ce/Al2O3 catalyst surface as well as the retarded sintering of PdO and the maintained oxidized state of surface Pd during the combustion process in the presence of Ce.