Suk Bong Hong

Diesel engine technology is still the most effective solution to meet tighter CO₂ regulations in the mobility and transport sector. In implementation of fuel-efficient diesel engines, the poor thermal durability of lean nitrogen oxides (NO_x ) aftertreatment systems remains as one major technical hurdle. Divalent copper ions when fully exchanged into high-silica LTA zeolites are demonstrated to exhibit excellent activity maintenance for NO_x reduction with NH<sub>3

The CO₂ adsorption behavior at 25-75 °C and 0-1.0 bar of various alkali cation-exchanged forms of merlinoite (framework type MER) zeolites with Si/Al=2.3 and 3.8 is described. The adsorption isotherms at 25 °C on the Na⁺ , K⁺ , Rb⁺ , and Cs⁺ forms of MER zeolite with Si/Al=2.3 are characterized by a clear step, the CO₂ pressure of which differs notably according to the type of their extraframework cations. Structural analysis show

The synthesis, crystal structure, characterization, and catalytic properties of the novel medium-pore zeolite TNU-9 (framework type TUN), one of the most crystallographically complex zeolites known to date, are described. TNU-9 was found to crystallize under hydrothermal conditions at the expense of a lamellar precursor over a very narrow range of SiO(2)/Al(2)O(3) and NaOH/SiO(2) ratios and in the presence of 1,4-bis(N-methylpyrrolidinium)butane and Na+ ions as structure-directing agents. A comb

27Al magic-angle spinning (MAS) and triple quantum (3Q) MAS NMR spectroscopic techniques were used to characterise zeolite Beta samples with framework Si/Al ratios between 9 and 215, obtained by synthesis in fluoride medium. A carefully controlled stepwise calcination procedure was adopted to obtain H-Beta. A partial resolution of the T-sites was observed in the 27Al MAS NMR spectra, the resolution increasing with increasing the Si/Al ratios. The relative intensity of these peaks varied graduall

Zeolites and related crystalline microporous materials with cavities and channels of molecular dimensions are of major importance for applications ranging from ion-exchange to adsorption and to catalysis. Because their unique shape-selective properties are closely related to the size, shape, and dimensionality of the intracrystalline channels and cavities, much interest has been devoted to the discovery of novel zeolitic materials over the last several decades. As a result, a dramatic expansion

A high-silica zeolite (Si/Al = 7.1) with the STI framework topology, denoted TNU-10, has been synthesized in the presence of 1,4-bis(N-methylpyrrolidinium)butane and Na(+) cations as structure-directing agents, and its structure in the proton form has been refined against laboratory powder X-ray data in space group Fmmm (a = 13.533(1) A, b = 17.925(2) A, c = 17.651(2) A). The space group symmetry is supported by electron diffraction and energy minimization studies. The as-made and proton form of

UCSB-6 (framework type <b>SBS</b>) and UCSB-10 (<b>SBT</b>), two three-dimensional phosphate-based molecular sieves with supercages accessible through 12-ring (circumscribed by 12 tetrahedral atoms) windows, are structurally similar to the hexagonal and cubic polytypes of faujasite or zeolite Y, an industrially relevant catalyst, but the cage structures are substantially different. Nonetheless, their inherent thermal instability has precluded any catalytic application so far. By using multiple i