| Summary: | SAPO-34 molecular sieves were synthesized under hydrothermal conditions using different combinations of tetraethyl ammonium hydroxide (TEAOH)/morpholine (Mor)/triethylamine (TEA) as templates, with different silicon:aluminum ratios. The physicochemical properties of the synthesized SAPO-34 were characterized using XRD, SEM, N<sub>2</sub> adsorption⁻desorption, XRF, TG, NH<sub>3</sub>-TPD, FT-IR, and <sup>29</sup>Si MAS NMR analyses. According to the SEM and the N<sub>2</sub> adsorption⁻desorption of the catalysts produced by the ternary template exhibited a larger surface area and a smaller crystal size than those produced by the single or binary templates. The FT-IR analysis indicated the increased acidity of the catalyst prepared by the ternary template. A high activity and selectivity to olefins (C<sub>2</sub><sup>=</sup> + C<sub>3</sub><sup>=</sup>) and an optimal silicon to aluminum ratio of 0.4 were obtained from the catalyst synthesized with the ternary template. At the reaction temperature of 450 °C, the methanol conversion approached 100% and the ethylene⁻propylene selectivity and the lifetime of the catalyst reached maximums of 89.15% and 690 min, respectively.
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