2017/01/31 by Seyed Hesam Mousavia, Mousavia, Seyed Hesam, Shohreh Fatemi +3
Chemistry · Environmental Science · Materials Science · #Chemical Synthesis and Characterization #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Metal-Organic Frameworks: Synthesis and Applications #Polyoxometalates: Synthesis and Applications #Zeolite Catalysis and Synthesis
paper · pdf · doi:10.48550/arxiv.1701.09159
openalex publication_date 2017/01/31 · openalex created_date 2022/10/01 · openalex updated_date 2026/07/28
Modified structures of SAPO-34 were prepared using polyethylene glycol as the\nmesopores generating agent. The synthesized catalysts were applied in\nmethanol-to-olefins (MTO) process. All modified synthesized catalysts were\ncharacterized via XRD, XRF, FESEM, FTIR, N2 adsorption-desorption techniques,\nand temperature-programmed NH3 desorption and they were compared with\nconventional microporous SAPO-34. Introduction of non-ionic PEG capping agent\naffected the degree of homogeneity and integrity of the synthesis media and\nthus reduced the number of nuclei and order of coordination structures\nresulting in larger and less crystalline particles compared with the\nconventional sample. During the calcination process, decomposition of absorbed\nPEG moieties among the piled up SAPO patches formed a great portion of tuned\nmesopores into the microporous matrix. These tailored mesopores were served as\nauxiliary diffusion pathways in MTO reaction. The effects of molecular weight\nof PEG and PEG/Al molar ratio on the properties of the synthesized materials\nwere investigated in order to optimize their MTO reaction performance. It was\nrevealed that both of these two parameters can significantly change the\nstructural composition and physicochemical properties of resultant products.\nUsing PEG with MW of 6000 has led to the formation of RHO and CHA structural\nframeworks i.e. DNL-6 and SAPO-34, simultaneously, while addition of PEG with\nMW of 4000 resulted the formation of pure SAPO-34 phase. Altering the PEG/Al\nmolar ratio in the precursor significantly influenced the porosity and acidity\nof the synthesized silicoaluminophosphate products. SAPO-34 impregnated with\nPEG molecular weight of 4000 and PEG/Al molar ratio of 0.0125 showed superior\ncatalytic stability in MTO reaction because of the tuned bi-modal porosity and\ntailored acidity pattern.\n