We report herein a facile synthesis of fullerene-like cages, which can be opened and closed through simple thermal treatments. A glassy carbon with enclosed fullerene-like cages of 2-3 nm was synthesized through a soft-template approach that created open mesopores of 7 nm. The open mesopores provided access to the fullerene-like cages, which were opened and closed through heat treatments in air and inert gas at various temperatures. Catalytic measurements showed that the open cages displayed strikingly higher activity for the oxidative dehydrogenation of isobutane in comparison to the closed ones. We anticipate that this synthesis approach could unravel an avenue for pursuing fundamental understanding of the unique catalytic properties of graphitic carbon nanostructures.

Open-Cage Fullerene-like Graphitic Carbons as Catalysts for Oxidative Dehydrogenation of Isobutane [J. Am. Chem. Soc. 2009, 131, 7735―7741]

Novel montmorillonite-nanosheet/chitosan (MMTNS/CS) hydrogels fabricated via the self-assembly of exfoliated MMTNS and CS chains were investigated. The exfoliation of MMTNS, self-assembly mechanism and structure of MMTNS/CS hydrogels were characterized by an atomic force microscope, scanning electron microscope, transmission electron microscope, Fourier transform infrared spectroscope, energy-dispersive x-ray spectroscope and Brunauer-Emmett-Teller analyzer, respectively. The results indicated that MMT could be easily exfoliated to nanosheets with a thickness of 1 ∼ 5 nm in aqueous solution by an ultrasonic base upon interlayer hydration. The formation mechanism of the self-assembly hydrogels was due to the hydrogen bond (-OH ··· +NH3-) and electrostatic interaction between the MMTNS and CS. The MMTNSs were connected consecutively by CS in-plane to form a huge slice. The porous structure of the hydrogels was controllable by adjusting the MMTNS/CS mass ratio. The hydrogels could be used as adsorbents for sewage treatments, carriers for drugs, microorganisms and catalyzers due to their controllable porous structure and tremendous specific surface area which were derived from the completely exfoliated MMTNS.

https://iopscience.iop.org/article/10.1088/1361-6528/aa9ba4/pdf

Preparation and characterization of self-assembly hydrogels with exfoliated montmorillonite nanosheets and chitosan.

Dehydrogenation of methylcyclohexane over PtSn supported on MgAl mixed metal oxides derived from layered double hydroxides

Fabrication of highly dispersed Pt-based catalysts on γ-Al2O3 supported perovskite Nano islands: High durability and tolerance to coke deposition in propane dehydrogenation

Activated or porous carbon is a carbonaceous material which has excellent adsorption capacity. Activated carbon has many applications including heavy metal and toxic gas removal as well as air and water filter applications. Microporous activated carbon in spherical shape (activated or porous carbon spheres) is a variant of activated carbon which has high compressive strength and low ash content. Pitch, polymeric (phenolic and sulfonated polystyrene resins) and other precursor materials (carbohydrate and seeds) have been generally used for production of activated carbon spheres employing carbonization and activation processes. Various parameters viz. carbonization temperature, heating rate, activation time and temperature, and activation media affected the performance and quality of end product. Generally activation by physical and chemical means is used for activated carbon spheres preparation. The use of polymeric precursors yielded better compressive strength and minimal ash content in comparison to other precursors. Activated carbon spheres produced using these processes has been successfully utilized as adsorbent materials for removal of heavy metals, organic dye, carbon dioxide, volatile organic chemicals, support for catalyst, gas and energy storage and also in chemical protective clothings. In present review, we discuss latest developments in activated carbon spheres and its use as adsorbent materials for removal of toxicants and various other applications.

Porous carbon spheres: Recent developments and applications

Facile preparation of PtSn-La/Al2O3 catalyst with large pore size and its improved catalytic performance for isobutane dehydrogenation

This study provides a detailed report on the synthesis of spherical activated carbon with mesoporous structure using a soluble low molecular weight phenolic resol precursor through an ammonium alginate assisted sol–gel method. The effects of calcinating temperature and the addition of CaCO3 as a pore-enlarging agent on texture structure and catalytic performance in isobutane dehydrogenation to isobutene were investigated. Characterization of N2 sorption, mechanical strength tests, and optical photographs confirmed that the obtained carbon materials had high mechanical strength, a good degree of sphericity, and a large surface area. Introducing CaCO3 as a pore-enlarging agent during the preparation process promoted the formation of a mesoporous structure of carbon spheres and evidently increased the surface area and oxygen content, which can improve isobutane conversion and isobutene selectivity of these carbon spheres. The conversion of isobutane reached up to 28% for this spherical activated carbon, and the selectivity of isobutene reached up to 96%. Isobutane conversion increased with an increase in calcination temperature due to an increase in the oxygen content, whereas the selectivity of isobutene decreased due to the slight decrease in the specific surface area.

Simple Preparation of Spherical Activated Carbon with Mesoporous Structure from Phenolic Resol and Associated Catalytic Performance in Isobutane Dehydrogenation

Using petrol to supply energy for a car or burning coal to heat a building generates plenty of greenhouse gas (GHG) emissions, including carbon dioxide (CO2 ), water vapor (H2 O), methane (CH4 ), nitrous oxide (N2 O), ozone (O3 ), fluorinated gases. These up-and-coming metal-organic frameworks (MOFs) are structurally endowed with rigid inorganic nodes and versatile organic linkers, which have been extensively used in the GHG-related applications to improve the lives and protect the environment. Porous MOF materials and their derivatives have been demonstrated to be competitive and promising candidates for GHG separation, storage and conversions as they shows facile preparation, large porosity, adjustable nanostructure, abundant topology, and tunable physicochemical property. Enormous progress has been made in GHG storage and separation intrinsically stemmed from the different interaction between guest molecule and host framework from MOF itself in the recent five years. Meanwhile, the use of porous MOF materials to transform GHG and the influence of external conditions on the adsorption performance of MOFs for GHG are also enclosed. In this review, it is also highlighted that the existing challenges and future directions are discussed and envisioned in the rational design, facile synthesis and comprehensive utilization of MOFs and their derivatives for practical applications.

An-hua Dong

Papers

Facile preparation of PtSn-La/Al2O3 catalyst with large pore size and its improved catalytic performance for isobutane dehydrogenation

Simple Preparation of Spherical Activated Carbon with Mesoporous Structure from Phenolic Resol and Associated Catalytic Performance in Isobutane Dehydrogenation

Metal-Organic Frameworks for Greenhouse Gas Applications.