One-pot fabrication of metal-zeolite catalysts from a combination of solvent-free and sodium-free routes

Abstract

The metal-exchanged zeolites as catalysts have been widely applied in many catalytic reactions, but their syntheses are environmentally unfriendly due to the multiple steps such as ion-exchange for the formation of a large amount of wastes. Herein, we for the first time report a method for one-pot fabrication of metal-zeolite catalysts (M-SSZ-13, M-Beta, M-ZSM-5, and M-EU-1; M = Cu, Co, Ni) from a combination of solvent-free and sodium-free routes by mixing, grinding, and heating the raw materials of aluminosilicate gel, organic templates, and metal-amine complexes. As a typical example, Cu-SSZ-13 zeolite is successfully synthesized from heating the mixture of aluminosilicate gel, organic template, and Cu-amine complex. Catalytic tests in selective catalytic reduction of NOx with NH3 (NH3-SCR) show that the synthesized Cu-SSZ-13 zeolite before and after hydrothermal aging at 750 °C for 16 h are completely comparable with the commercial Cu-SSZ-13 zeolite from the conventional hydrothermal synthesis. Very interestingly, the method in this work has obvious advantages such as high yield, reduced pollutants, and simple process, which should be potentially important for practical applications of the metal-zeolites in the future.