Synthesis and study of λ-MnO_2 supported Pt nanocatalyst for methanol electro-oxidation

A λ-MnO2 supported Pt nanocatalyst（5 wt.% Pt/λ-MnO2） was synthesized using a facile approach.X-ray diffraction（XRD）, X-ray photoelectron spectroscopy（XPS）, scanning electronic microscope（SEM）, transmission electron microscopy（TEM）, and energy disperse spectroscopy（EDS） were used for catalyst structure and morphology characterization, which showed that the metallic Pt particles were attached on a λ-MnO2 surface through the interaction between Pt and λ-MnO2.Cyclic voltammetry（CV） was used to test the catalytic activity of Pt/λ-MnO2 toward methanol oxidation, which showed that Pt/λ-MnO2 catalyst has much higher catalytic activity than baseline Pt/C catalyst.

The Effect of Rare Earth on the Activity of Methanol Synthesis Catalyst

In this paper several rare earth oxides were added into methanol synthesis catalyst by solid-mixing method to improve the activity of methanol synthesis catalyst. Nd2O3, CeO2, La2O3 and Sm2O3 decrease the catalyst activity, while Pr2O3, Gd2O3 and Eu2O3 increase the methanol yield.

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.

NC310 Catalyst for Methanol Synthesis Developed by SINOPEC Research Institute of Nanjing Chemical Company

The NC310 type catalyst for methanol synthesis developedby the SINOPEC Research Institute of NanjingChemical Company has passed the appraisal of researchachievements organized by the Science and TechnologyDivision of the Sinopec Corp. The group of specialistsattending the appraisal meeting has recognized that thiscatalyst has reached the internationally advanced level interms of its overall catalytic performance.

Effect of Cu-ZnO-Al_2O_3 supported on H-ferrierite on hydrocarbons formation from CO hydrogenation

Methanol synthesis catalysts based on Cu, Zn and Al were prepared by three methods and subsequently mixed with H-ferrierite zeolite in an aqueous suspension to disperse the catalysts over the support. These materials were characterized by X-ray diffraction, N2 adsorption, transmission electron microscopy, temperature programmed reduction, NH3 and H2 temperature-programmed desorption, and X-ray photoelectron spectroscopy. They were also applied to the CO hydrogenation reaction to produce dimethyl ether and hydrocarbons. The catalysts were prepared by coprecipitation under low and high supersaturation conditions and by a homogeneous precipitation method. The preparation technique was found to affect the precursor structural characteristics, such as purity and crystallinity, as well as the particle size distribution of the resulting catalyst. Low supersaturation conditions favored high dispersion of the Cu species, increasing the methanol synthesis catalyst＇s metallic surface area and resulting in a homogeneous particle size distribution. These effects in turn were found to modify the zeolite properties, promoting both a low micropore volume and blockage of the zeolite acid sites. The effect of the methanol synthesis catalyst on the reaction was verified by the correlation between the Cu surface area and the CO conversion rate.

Kinetic studies of methanol synthesis from CO_2+H_2 over copper based catalysts

The catalytic activity for the synthesis of methanol from carbon dioxide and hydrogen was measured on various binary and ternary catalysts containing copper oxide under a pressure of 10 atm. Among these samples the catalysts, CuO/ZnO/γ-Al_2O_3, demonstrated the highest activity and selectivity to methanol; MnO, as third component, had no promotional effect on the activity of meth- anol formation. Based on a simple power rate law the apparent activation energy estimation and par- tial pressure dependence measurement were accomplished over eight catalysts. The activation energies varied from 40 to 120 kJ / mol depending on the composition of catalysts. The rates of methanol for- mation to be 0.3 -- 0.9 order in H_2 and about 0.1 -- 0.2 order in CO_2 were reported.

SnNi nanoneedles assembled 3D radial nanostructure loaded with SnNiPt nanoparticles： Towards enhanced electrocatalysis performance for methanol oxidation

A desirable methanol oxidation electrocatalyst was fabricated by metal atom diffusion to form an alloy of an assembled three-dimensional （3D） radial nanostructure of SnNi nanoneedles loaded with SnNiPt nanoparticles （NPs）.Herein,metal atom diffusion occurred between the SnNi support and loaded Pt NPs to form a SnNiPt ternary alloy on the catalyst surface.The as-obtained catalyst combines the excellent catalytic performance of the alloy and advantages of the 3D nanostructure;the SnNiPt NPs,which fused on the surface of the SnNi nanoneedle support,can dramatically improve the availability of Pt during electrocatalysis,and thus elevate the catalytic activity.In addition,the efficient mass transfer of the 3D nanostructure reduced the onset potential.Furthermore,the catalyst achieved a favorable CO poisoning resistance and enhanced stability.After atomic interdiffusion,the catalytic activity drastically increased by 45%,and the other performances substantially improved.These results demonstrate the significant advantage and enormous potential of the atomic interdiffusion treatment in catalytic applications.

Microfibrous entrapped ZnO-CaO/Al_2O_3 for high efficiency hydrogen production via methanol steam reforming

Sinter-locked microfibrous networks consisting of -3 vol.% of 8 p.m （dia.） nickel microfibers have been utilized to entrap -30vo1.% of 100-200 μm dia. porous AI203. ZnO and CaO were then highly dispersed onto the pore surface of entrapped A1203 by the incipient wetness impregnation method. Due to the unique combination of surface area, pore size/particle size, thermal conductivity, and void volume, the resulting microfibrous catalyst composites provided significant improvement of catalytic bed reactivity and utilization efficiency when used in methanol steam reforming. Roughly 260 mL/min of reformate, comprising 〉70% H2, 〈5% CO and trace CH4, with 〉97% methanol conversion, could be produced in a I cm3 bed volume of our novel microfihrous entrapped ZnO-CaO/Al2O3 catalyst composite at 470℃ with a high weight hourly space velocity （WHSV） of 15 h-1 using steam/methanol （1.3/1） mixture as feedstock. Compared to a packed bed of 100-200μm ZnO-CaO/Al2O3, our composite bed provided a doubling of the reactor throughput with a halving of catalyst usage.

Hydrogen generation from methanol reforming under unprecedented mild conditions

A homogeneous catalyst [Cp＊Rh（NH3）（H2O）2]-（3＋） has been found for the clean conversion of methanol and water to hydrogen and carbon dioxide. The simple and easily available reaction steps can circumvent the formation of CO, therefore, making it possible to avoid inactivating catalysts and contaminating the hydrogen fuel. Different from conventional reforming method for hydrogen production, no additional alkaline or organic substances are required in this method. Valuable hydrogen can be obtained under ambient pressure at 70 C, corresponding TOF is 83.2 h 1. This is an unprecedented success in reforming methanol to hydrogen. Effects of reaction conditions, such as reaction temperature, initial methanol concentration and the initial p H value of buffer solution on the hydrogen evolution are all systematically investigated. In a certain range, higher reaction temperature will accelerate reaction rate. The slightly acidic condition is conducive to rapid hydrogen production. These findings are of great significance to the present establishment of the carbon-neutral methanol economy.