Mixed templates application in ZSM-5 nanoparticles synthesis: Effect on the size, crystallinity, and surface area

Abstract

ZSM-5 nanoparticles of 50–100nm size were synthesized by simultaneously adding tetrapropylammonium hydroxide and bromide using the following stoichiometry: NaAlO2: 25 SiO2: x TPAOH: y TPABr: 0.033 Na2O: 1000 H2O in which x+y is equal to 9.The synthesized samples were characterized by X-ray diffraction, field emission scanning electron microscope, transmission electron microscopy and Brunauer–Emmett–Teller surface area analysis. Impacts of various ratios of tetrapropylammonium hydroxide to tetrapropylammonium bromide, on size, crystallinity and surface were examined and it was found that in 6 tetrapropylammonium bromide to 3 tetrapropylammonium hydroxide mixed templates optimized ratio, the smallest size with the biggest surface and high crystallinity was achieved. Using tetrapropylammonium bromide template only for synthesis of ZSM-5 in high molar stoichiometry ratio (9 tetrapropylammonium bromide) in synthesis gel lead to get amorphous particles because of the synthesis gel sharp pH drop during crystallization.