Continuity Control of b-Oriented MFI Zeolite Films by Microwave Synthesis

Influences of aging and crystallization conditions on the continuity of b-oriented MFI zeolite films on stainless steel substrates are systematically investigated. A long aging time (e.g., 20 h) at room temperature is needed to obtain a continuous b-oriented MFI zeolite film by the microwave heating at 165 degrees C. However, the aging time can be shortened from 20 h to 30 min by elevating the aging temperature to 80 degrees C. Compared with the conventional heating (2 h), continuous b-oriented MFI zeolite films are prepared on stainless steel substrates with a much shorter crystallization time by the microwave heating (35 min). Continuous b-oriented MFI zeolite films can be synthesized by controlling nuclei concentration and crystal size, which are mainly determined by the conditions of the aging and crystallization respectively. On the basis of the results from these experiments, a film continuity-synthesis condition map is obtained and a film formation mechanism is discussed.