Direct CO2 hydrogenation to light olefins over ZnZrOx mixed with hierarchically hollow SAPO-34 with rice husk as green silicon source and template

• Published in: Applied catalysis. B, Environmental Vol. 315; p. 121572
• Main Authors: Tian, Pan, Zhan, Guowu, Tian, Jian, Tan, Kok Bing, Guo, Meiting, Han, Yating, Fu, Tingjun, Huang, Jiale, Li, Qingbiao
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.10.2022
• Subjects: Bifunctional catalysts; CO2 hydrogenation; Hollow SAPO-34; Light olefins; Tandem catalysis; Bifunctional catalysts; Light olefins; Tandem catalysis; CO2 hydrogenation; Hollow SAPO-34
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2022.121572

Here, we present a new preparation strategy for hollow SAPO-34 with hierarchical porous structures using rice husk as a sole silicon source and porous template (viz., bio-SAPO-34). The hollow feature and acidity amount of the bio-SAPO-34 were highly dependent on the amount of rice husk in the synthetic solutions. The bio-SAPO-34 exhibited very high olefin selectivity (94.5 %) in the methanol-to-olefins reaction. Bifunctional catalysts consisting of ZnZrOx and bio-SAPO-34 were fabricated for the direct conversion of CO2 to light olefins. The C2=-C4= selectivity of 83 % and C2=-C4= space-time yield of 6.14 mmol gcat−1 h−1 was achieved with only 1 % undesired CH4 at 13.8 % CO2 conversion. Particularly, the CO selectivity from the reverse water-gas shift reaction was suppressed to a low value (40 %). Furthermore, the in-situ DRIFTS result indicates that CH3O* is the key intermediate forming on the ZnZrOx surface and transferring to the Brønsted acid site of bio-SAPO-34 for selective C-C coupling. [Display omitted] •Hollow SAPO-34 was prepared using rice husk as silicon source and template.•Bio-SAPO-34 showed different characters as compared to the conventional SAPO-34.•CO2 hydrogenation to light olefins was realized over the integrated nanocatalysts.•High C2=-C4= selectivity of 83 % and C2-C4 selectivity of 99 % were achieved.•Bifunctional catalyst showed high stability with good resistance to coke formation.