다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Based on first-principles plane wave calculations, we showed that Ca adsorbed on graphene can serve as a high-capacity hydrogen storage medium, which can be recycled by operations at room temperature. Ca is chemisorbed by donating part of its $4s$ charge to the empty ${\ensuremath{\pi}}^{\ensuremath{\ast}}$ band of graphene. At the end the adsorbed Ca atom becomes positively charged and the semimetallic graphene changes into a metallic state. While each of the adsorbed Ca atoms forming the $(4\ifmmode\times\else\texttimes\fi{}4)$ pattern on the graphene can absorb up to five ${\text{H}}_{2}$ molecules, hydrogen storage capacity can be increased to $8.4\text{ }\text{wt}\text{ }%$ by adsorbing Ca to both sides of graphene and by increasing the coverage to form the $(2\ifmmode\times\else\texttimes\fi{}2)$ pattern. Clustering of Ca atoms is hindered by the repulsive Coulomb interaction between charged Ca atoms.

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Hydrogen storage of calcium atoms adsorbed on graphene: First-principles plane wave calculations

A review of recent developments in hydrogen production via biogas dry reforming

Propylene is an important building block for enormous petrochemicals including polypropylene, propylene oxide, acrylonitrile and so forth. Propane dehydrogenation (PDH) is an industrial technology for direct propylene production which has received extensive attention in recent years. With the development of dehydrogenation technologies, the efficient adsorption/activation of propane and subsequential desorption of propylene on the surfaces of heterogeneous catalysts remain scientifically challenging. This review describes recent advances in the fundamental understandings of the PDH process in terms of emerging technologies, catalyst development and new chemistry in regulating the catalyst structures and inhibiting the catalyst deactivation. The active sites, reaction pathways and deactivation mechanisms of PDH over metals and metal oxides as well as their dependent factors are also analysed and discussed, which is expected to enable efficient catalyst design for minimizing the reaction barriers and controlling the selectivity towards propylene. The challenges and perspectives of PDH over heterogeneous catalysts are also proposed for further development.

Propane dehydrogenation: catalyst development, new chemistry, and emerging technologies

Oxygen vacancy is conducive to molecular oxygen adsorption and activation, and it is necessary to estimate its contribution on catalysts, especially the doped system for volatile organic compound (VOC) oxidation. Herein, a series of doped Mn xZr1- xO2 catalysts with oxygen vacancy were prepared by partially substituting Zr4+ in a zirconia with low-valent manganese (Mn2+). Compared with the corresponding mechanically mixed samples (MB-x) without oxygen vacancy, Mn xZr1- xO2 catalysts exhibited better toluene conversion and specific reaction rate, where the differential values were calculated to estimate the contribution of oxygen vacancy on catalytic performance. The increase in oxygen vacancy concentrations in Mn xZr1- xO2 catalysts can boost the differential values, implying the enhancement of oxygen vacancy contribution. Density functional theory (DFT) calculations further confirmed the contribution of oxygen vacancy, and molecular oxygen is strongly absorbed and activated on a defective Mn-doped c-ZrO2 (111) surface with oxygen vacancy rather than a perfect m-ZrO2 (-111) surface or a perfect Mn-doped c-ZrO2 (111) surface, thus resulting in the significant improvement in catalytic activity for toluene oxidation. In situ DRIFTS spectra revealed that the oxygen vacancy can alter the toluene degradation pathway and accelerate the intermediates to convert into CO2 and H2O, thus leading to a low activation energy and high specific reaction rate.

Defective Mn x Zr 1- x O 2 Solid Solution for the Catalytic Oxidation of Toluene: Insights into the Oxygen Vacancy Contribution.

Enhanced hydrogen storage on Li-doped defective graphene with B substitution: A DFT study

A new self-propagated flaming (SPF) technique was applied to the synthesis of highly active layered CuO-δ-MnO2 hybrid composites, for the de-polluting catalytic total oxidation of gaseous toluene vapor. Other transition metal oxide-doped MnO2 hybrid composites were also successfully prepared and investigated, ensuring a feasible strategy for the fabrication of various layered MOx-δ-MnO2 (M═Co, Ni, or Zn) hybrids. By changing the molar ratio of the precursors (KMnO4 and acetate salt) and the type of transition metal oxide introduced, it is possible to control the crystal structure and reducibility of the sheetlike hybrid composites as well as the catalytic activity for the total oxidation of toluene. The catalyst sample (CuO-δ-MnO2) with a Mn/Cu molar ratio of 10:1 exhibited the highest catalytic performance, with a lower reaction temperature of 300 °C for complete toluene removal, which was comparable to the reaction temperature for total toluene conversion by the Pt-based catalyst. The SPF technique prov...

Self-Propagated Flaming Synthesis of Highly Active Layered CuO-δ-MnO2 Hybrid Composites for Catalytic Total Oxidation of Toluene Pollutant

CeO2 nanorods supported nickel catalysts were prepared by wetness impregnation method, using nickel nitrate and nickel chloride as nickel sources. The dried catalyst precursors were decomposed either by thermal calcination or glow discharge plasma technique. The effects of precursor decomposition methods and nickel sources on the catalytic performance of glycerol steam reforming were then investigated. Characterization and catalytic results showed that glow discharge plasma treatment instead of thermal calcination enhanced the nickel dispersion, improved the Ni-Ce interaction and led to the formation of Ni-O-Ce composite, which could both enhance the H2 selectivity and restrain the coke deposition during reaction. Thus, no deactivation was observed on the two plasma treated catalysts throughout the tests. Nickel source may influence both rate of particle sintering and carbonaceous deposition during reaction; fast nickel sintering but slower coke deposition was found on the catalysts prepared from nickel chloride, and coke deposition was more detrimental to active sites decrease than nickel sintering.

Fangli Jing

Papers

Enhanced hydrogen storage on Li-doped defective graphene with B substitution: A DFT study

Self-Propagated Flaming Synthesis of Highly Active Layered CuO-δ-MnO2 Hybrid Composites for Catalytic Total Oxidation of Toluene Pollutant

Preparation of stable and highly active Ni/CeO2 catalysts by glow discharge plasma technique for glycerol steam reforming

Highly effective self-propagating synthesis of CeO2-doped MnO2 catalysts for toluene catalytic combustion

Enhanced catalytic performances of in situ-assembled LaMnO3/δ-MnO2 hetero-structures for toluene combustion