New CoO−SiO₂-Sol Pillared Clays as Catalysts for NO_x Conversion

Abstract

New CoO−SiO2-sol pillared montmorillonite (Co−SiM) is synthesized by interlamellar hydrolysis and condensation of tetraethyl orthosilicate (TEOS) in the presence of Co2+ ion via an alkylammonium intercalated montmorillonite. The silicate layers of Na+−montmorillonite are expanded in advance with hexadecyltrimethylammonium cation up to ∼22 Å, followed by reaction with a mixed sol solution of TEOS and CoCl2·6H2O in the presence of n-dodecylamine as a cotemplate. A microporous Co−SiM is obtained after removing the organic templates at 550 °C. The nitrogen adsorption−desorption isotherm for the pillared sample reveals that a large number of micropores are created between the silicate layers, giving rise to a high BET specific surface area (S BET = ∼570 m2/g) and a pore volume (V = ∼0.65 mL/g). According to the X-ray photoelectron and X-ray absorption spectroscopy, the incorporated cobalt species is found to be CoO, which is homogeneously dispersed on the surface of the SiO2 pillars. The Co−SiM exhibits an excellent NO conversion rate of ca. 50% at 200 °C, which continuously increases up to 80% at 500 °C.

Growth of Carbon Nanotubes on Clay: Unique Nanostructured Filler for High‐Performance Polymer Nanocomposites

“…[2,3] Here, we propose a new class of radiation-detection materials, composites of inorganic semiconductor quantum dots and organic semiconductors, that possess the cost and processing advantages of organic scintillators and the ionization characteristics of inorganic semiconductors. The qdot/organic semiconductor composite is designed so that ionizing radiation produces excitations predominantly in the inorganic semiconductor qdots, and these excitations are subsequently Förster-transferred [4] to the organic material.…”

“…Because of its large surface area, strong acidity, and strong adsorption and ion-exchange ability, clay has been widely used as a catalyst and catalytic support for years. [1][2][3] For example, clay-supported cobalt oxide is the catalyst for the de-NO x reaction, [4] while clay-supported iron oxide has been used as a Fischer-Tropsch catalyst. [5] As has been demonstrated, iron, nickel, or cobalt nanoparticles supported on oxides are efficient catalysts for the synthesis of carbon nanotubes (CNTs) by chemical vapor deposition (CVD), which has proven to be a cost-efficient way of mass producing CNTs.…”

Photocatalytic conversion of NO using TiO2–NH3 catalysts in ambient air environment

“…To abate the NO x emission, various de-NOx technologies have been developed with recent improvements [4][5][6][7][8][9][10][11][12]. Selective catalytic reduction (SCR) processes were applied at some stationary emission sources such as power plants, waste incinerators, and industrial boilers to transfer NO x into N 2 and H 2 O at high temperature [4][5][6][7][8].…”

“…Selective catalytic reduction (SCR) processes were applied at some stationary emission sources such as power plants, waste incinerators, and industrial boilers to transfer NO x into N 2 and H 2 O at high temperature [4][5][6][7][8]. Furthermore, with appropriate catalysts and reducing agents such as ammonia (NH 3 -SCR) or hydrocarbons (HC-SCR), the non-thermal plasma processes could be feasible to reduce nitric oxides synergistically into N 2 [7].…”

Polysilsesquioxane Nanosheets Synthesized in Confined Environment

“…[5] Montmorillonite (MMT) is well known for its high aspect ratio structure and is widely used as a template to create various hybrid structures. [6][7][8][9][10][11] However, no literature has been reported to date on MMT acting as a template to prepare sheet-like polymers. We report here a study using MMT as a template to load an organic precursor and then allow polymerization to proceed in the confined layer space of MMT.…”