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

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

[Liu, Chang; Li, Feng; Ma, Lai-Peng; Cheng, Hui-Ming] Chinese Acad Sci, Inst Met Res, Shenyang Natl Lab Mat Sci, Shenyang 110016, Peoples R China.;Cheng, HM (reprint author), Chinese Acad Sci, Inst Met Res, Shenyang Natl Lab Mat Sci, 72 Wenhua Rd, Shenyang 110016, Peoples R China;cheng@imr.ac.cn

Advanced Materials for Energy Storage

Nitrogen-doped graphene (N-graphene) was synthesized by chemical vapor deposition of methane in the presence of ammonia. The resultant N-graphene was demonstrated to act as a metal-free electrode with a much better electrocatalytic activity, long-term operation stability, and tolerance to crossover effect than platinum for oxygen reduction via a four-electron pathway in alkaline fuel cells. To the best of our knowledge, this is the first report on the use of graphene and its derivatives as metal-free catalysts for oxygen reduction. The important role of N-doping to oxygen reduction reaction (ORR) can be applied to various carbon materials for the development of other metal-free efficient ORR catalysts for fuel cell applications, even new catalytic materials for applications beyond fuel cells.

/pdf/nitrogen-doped-graphene-as-efficient-metal-free-2c5sl934bm.pdf

Nitrogen-Doped Graphene as Efficient Metal-Free Electrocatalyst for Oxygen Reduction in Fuel Cells

Hollow micro-/nanostructures are of great interest in many current and emerging areas of technology. Perhaps the best-known example of the former is the use of fly-ash hollow particles generated from coal power plants as partial replacement for Portland cement, to produce concrete with enhanced strength and durability. This review is devoted to the progress made in the last decade in synthesis and applications of hollow micro-/nanostructures. We present a comprehensive overview of synthetic strategies for hollow structures. These strategies are broadly categorized into four themes, which include well-established approaches, such as conventional hard-templating and soft-templating methods, as well as newly emerging methods based on sacrificial templating and template-free synthesis. Success in each has inspired multiple variations that continue to drive the rapid evolution of the field. The Review therefore focuses on the fundamentals of each process, pointing out advantages and disadvantages where appropriate. Strategies for generating more complex hollow structures, such as rattle-type and nonspherical hollow structures, are also discussed. Applications of hollow structures in lithium batteries, catalysis and sensing, and biomedical applications are reviewed.

Hollow Micro-/Nanostructures: Synthesis and Applications**

Zeolitic imidazolate frameworks (ZIFs) represent a new and special class of metal organic frameworks comprised of imidazolate linkers and metal ions, with structures similar to conventional aluminosilicate zeolites Their intrinsic porous characteristics, abundant functionalities as well as exceptional thermal and chemical stabilities have led to a wide range of potential applications for various ZIF materials Explosive research activities ranging from synthesis approaches to attractive applications of ZIFs have emerged in this rapidly developing field in the past 5 years In this review, the development and recent progress towards different synthesis strategies to generate both powder and membrane/film-based ZIF materials are analysed and summarised Their attractive and potential applications in gas separation, catalysis, sensing and electronic devices, and drug delivery in the past years are discussed and reviewed In addition, the prospects and potential new development of ZIF materials are presented

Zeolitic imidazolate framework materials: recent progress in synthesis and applications

We report the synthesis of zeolite-like carbon materials that exhibit well-resolved powder XRD patterns and very high surface area. The zeolite-like carbons are prepared via chemical vapor deposition (CVD) at 800 or 850 °C using zeolite β as solid template and acetonitrile as carbon precursor. The zeolite-like structural ordering of the carbon materials is indicated by powder XRD patterns with at least two well-resolved diffraction peaks and TEM images that reveal well-ordered micropore channels. The carbons possess surface area of up to 3200 m2/g and pore volume of up to 2.41 cm3/g. A significant proportion of the porosity in the carbons (up to 76% and 56% for surface area and pore volume, respectively) is from micropores. Both TEM and nitrogen sorption data indicate that porosity is dominated by pores of size 0.6−0.8 nm. The carbon materials exhibit enhanced (and reversible) hydrogen storage capacity, with measured uptake of up to 6.9 wt % and estimated maximum of 8.33 wt % at −196 °C and 20 bar. At 1 b...

Enhanced Hydrogen Storage Capacity of High Surface Area Zeolite-like Carbon Materials

Synthesis of Ordered Mesoporous Carbon and Nitrogen-Doped Carbon Materials with Graphitic Pore Walls via a Simple Chemical Vapor Deposition Method

Zeolite-templated, high-surface-area, microporous, N-doped carbons exhibit the highest CO2 uptake capacity recorded to date for any carbon material and one of the highest for any inorganic or organic porous material of up to 6.9 mmol g−1 at 273 K and ambient pressure and 4.4 mmol g−1 at ambient temperature and pressure, along with an initial CO2 adsorption energy of 36 kJ mol−1 at lower coverage and 20 kJ mol−1 at higher CO2 coverage. Combined with their ease of preparation, excellent recyclability and regeneration stability, and high selectivity for CO2, the N-doped zeolite-templated carbons are amongst the most promising solid-state absorbents reported so far for CO2 capture and storage.

Superior CO2 Adsorption Capacity on N‐doped, High‐Surface‐Area, Microporous Carbons Templated from Zeolite

The development of highly efficient hydrogen storage materials is one of the main challenges that must be tackled in a widely expected hydrogen economy. Physisorption in porous materials with high surface areas and chemisorption in hydrides are the two main options for solid state hydrogen storage, and both options possess their inherent advantages and drawbacks. In this work, recent progress towards porous carbon-based materials for hydrogen storage is analyzed and reviewed. The hydrogen storage performance of plain porous carbons, metal-supported porous carbons and porous carbons confined hydrides is summarized. Some strategies for effectively controlling the hydrogen storage capacity and tuning the hydrogen adsorption enthalpy for porous carbon materials via appropriate manipulation of surface area, pore volume and pore size are discussed in detail. The new development of porous carbon-based materials for hydrogen storage is particularly emphasized.

Yongde Xia

Papers

Zeolitic imidazolate framework materials: recent progress in synthesis and applications

Enhanced Hydrogen Storage Capacity of High Surface Area Zeolite-like Carbon Materials

Synthesis of Ordered Mesoporous Carbon and Nitrogen-Doped Carbon Materials with Graphitic Pore Walls via a Simple Chemical Vapor Deposition Method

Superior CO2 Adsorption Capacity on N‐doped, High‐Surface‐Area, Microporous Carbons Templated from Zeolite

Porous carbon-based materials for hydrogen storage: advancement and challenges