Synthesis of SAPO-34 with small and tunable crystallite size by two-step hydrothermal crystallization and its catalytic performance for MTO reaction

► SAPO-34 crystallites with ∼160 nm were synthesized by two-step hydrothermal process. ► SAPO-34 with ∼160 nm possesses larger surface area and more acid site. ► SAPO-34 synthesized by two-step method is very excellent catalyst for MTO reaction. ► Olefins selectivity and lifetime of SAPO-34 with 160 nm can reach >94.9% and 10 h, respectively.