Enhanced synthetic efficiency of CHA zeolite crystallized at higher temperatures

High silica chabazite zeolite (CHA) is very important for selective catalytic reduction of NOx with ammonia (NH3-SCR), but its synthesis is time-consuming under conventional hydrothermal conditions (160 degrees C for 90-120 h). Herein, we report a novel strategy for highly efficient synthesis of CHA zeolite by means of fast crystallization at high temperatures in the absence of water solvent (240 degrees C for 1.5 h). X-ray diffraction, N-2-adsorption isotherms, inductively coupled plasma, scanning electron microscopy, Si-29 and Al-27 MAS NMR, as well as thermogravimetry-differential thermal analysis suggest that the samples have high quality. This concept significantly enhances the space-time yields (STY) for CHA zeolite prepared from high-temperature synthesis in the absence of water solvent (almost two orders of magnitude higher than those of conventional hydrothermal synthesis). Moreover, compared with hydrothermal synthesis, the samples obtained from fast crystallization at higher temperatures (Si/Al = 12, 2.0% Cu loading) shows enhanced catalytic performance at 350-550 degrees C in NH3-SCR.