Abstract: Effects of various phase ratios on structure properties of SAPO-34/CZA composite crystal prepared via coprecipitation coating method and its catalytic performance on CO2 hydrogenation to light olefins were investigated in this paper.These obtained products were characterized by XRD, FT-IR, SEM, BET, NH3-TPD and CO2-TPD techniques to investigate their crystalline phase, skeletal structure, morphology, pore structure and surface acidity and alkalinity.The results indicate that composite phase ratio posed significant impact on the structure properties and catalytic performance of SAPO-34/CZA bifunctional composite catalyst.SAPO-34/CZA catalyst with composite phase ratio of 1∶1 has the distinct characteristics with micropore and mesopore (microporous specific surface area of 53.15 m2·g-1, mesoporous specific surface area of 59.84 m2·g-1, specific surface area of 113.00 m2·g-1, total pore volume 0.41 cm3·g-1, average pore size 14.57 nm) system, novel coating structure and composite interface, indicating the existence of a distinct reaction path and a coupling reaction.Accordingly, the CO2 conversion and light olefins selectivity are reach to 64.80; and 49.68; respectively under the condition of reduction temperature of 285 ℃, reaction temperature of 325 ℃, the reaction pressure of 3.0 MPa, V(H2)/V(CO2) of 3.0 and space velocity of 3500 mL·g-1·h-1.Compared with the blending catalyst SAPO-34/CZA-M, the CO2 conversion and light olefins selectivity of the sample with composite phase ratio of 1∶1 are increase by 31.98; and 2.43;, respectively.

Key words: Effects of various phase ratios on structure properties of SAPO-34/CZA composite crystal prepared via coprecipitation coating method and its catalytic performance on CO2 hydrogenation to light olefins were investigated in this paper.These obtained products were characterized by XRD, FT-IR, SEM, BET, NH3-TPD and CO2-TPD techniques to investigate their crystalline phase, skeletal structure, morphology, pore structure and surface acidity and alkalinity.The results indicate that composite phase ratio posed significant impact on the structure properties and catalytic performance of SAPO-34/CZA bifunctional composite catalyst.SAPO-34/CZA catalyst with composite phase ratio of 1∶1 has the distinct characteristics with micropore and mesopore (microporous specific surface area of 53.15 m2·g-1, mesoporous specific surface area of 59.84 m2·g-1, specific surface area of 113.00 m2·g-1, total pore volume 0.41 cm3·g-1, average pore size 14.57 nm) system, novel coating structure and composite interface, indicating the existence of a distinct reaction path and a coupling reaction.Accordingly, the CO2 conversion and light olefins selectivity are reach to 64.80; and 49.68; respectively under the condition of reduction temperature of 285 ℃, reaction temperature of 325 ℃, the reaction pressure of 3.0 MPa, V(H2)/V(CO2) of 3.0 and space velocity of 3500 mL·g-1·h-1.Compared with the blending catalyst SAPO-34/CZA-M, the CO2 conversion and light olefins selectivity of the sample with composite phase ratio of 1∶1 are increase by 31.98; and 2.43;, respectively.