Abstract:
Molecular sieves, improved methods for their synthesis, and catalysts, systems and methods of using these molecular sieves as catalysts in a variety of processes such as abating pollutants in exhaust gases and conversion processes are described. The molecular sieves are made using a tailored colloid including an alumina source, a silica source and a structure directing agent.
Abstract:
Un precursor de zeolita que comprende partículas coloidales, cada partícula incluye alúmina, sílice y un primer agente director de estructura, las cantidades de alúmina, sílice y el primer agente director de estructura presentes en una cantidad suficiente para formar una zeolita del tipo de estructura CHA que tiene aberturas de poro de anillo de 8 miembros y unidades de construcción secundaria de doble anillo de seis miembros, en donde el primer agente director de estructura comprende un compuesto sustituido con adamantilo, las partículas coloidales tienen una relación molar de SiO2 a Al2O3 en el intervalo de 20 y 40, y la relación del primer agente director de estructura a la sílice es menor que 0,06.
Abstract:
The present disclosure generally provides a catalyst composition comprising a zeolite containing iron and/or copper with a reduced amount of extra-framework aluminum. The catalyst composition is useful to catalyze the reduction of nitrogen oxides in exhaust gas in the presence of a reductant.
Abstract:
Certain selective catalytic reduction (SCR) articles, systems and methods provide for high NOx conversion while at the same time low N2O formation. The articles, systems and methods are suitable for instance for the treatment of exhaust gas of diesel engines. Certain articles have zoned coatings disposed thereon, for example, a zoned coating comprising an upstream zone comprising a coating layer comprising a steam-activated iron-containing molecular sieve and a downstream zone comprising a coating layer comprising a high copper-containing molecular sieve.