2025 AIChE Annual Meeting

(195g) Bifunctional Structured Adsorbent-Catalyst Monoliths As Versatile Platform for Reactive Capture and Its Subsequent Conversion to Light Olefins

Authors

Cooperative and bifunctional materials (BFMs) that integrate adsorbents and catalysts offer a promising strategy for the reactive capture of CO₂ to produce valuable fuels and chemicals.1-3 This work details the development of structured, cooperative “bifunctional” materials (BFMs) consisting of (i) a high-temperature adsorbent and (ii) a heterogeneous catalyst, which enable single-bed CO₂ capture and utilization in oxidative ethane dehydrogenation (ODHE) and oxidative propane dehydrogenation (ODHP) processes. We developed and processed structured BFMs via 3D printing, combining CaO and CaO-CaZrO₃ as adsorbents with Ga-Ca-Cr₂O₃ metal oxides and Cr₂O₃/ZSM-5 as catalysts for the reactive capture of CO₂ and its subsequent conversion to light olefins (C₃H₆ and C₂H₄) via the oxidative dehydrogenation of C₃H₈ and C₂H₆ (CO₂-ODH). Three different Ga₁₋ₓCaₓ ratios were used to modify the catalyst surface characteristics and enhance C₂H₄ selectivity. In these formulations, Ga ions stabilize the oxygen lattice of the BFM, while Ca ions interact strongly with Cr to form CaCrO₄, thereby altering the oxygen species and enhancing the material’s basic properties. Under adsorption–reaction conditions at 600–650°C, the optimal BFM achieved excellent C₂H₄ and C₃H₆ selectivities of 95% and 52%, respectively, attributed to a balanced redox process and improved basicity, which facilitate efficient C₃H₈ and C₂H₆ conversion and rapid desorption of C₃H₆ and C₂H₄ without excessive oxidation.

References:

  1. K. Baamran, A. Rownaghi, Direct Conversion of CO2 to Olefins over a Cr2O3/ZSM-5@ CaO Cooperative and Bifunctional Material Under Isothermal Conditions, ACS Sus.Chem. & Eng. 12, 2024,17783-17792.
  2. K. Baamran, A. Rownaghi, Cooperative and Bifunctional Ga-Ca-Cr2O3@CaO Structured Monoliths as Versatile Platform for Reactive Capture of CO2 and its Subsequent Conversion to Ethylene, CEJ 511, 2025,161701.
  3. K. Baamran, S. Lawson, F. Rezaei, A. Rownaghi, Cooperative and Bifunctional Ga-Ca-Cr2O3@CaO Structured Monoliths as Versatile Platform for Reactive Capture of CO2 and its Subsequent Conversion to Ethylene, Acc.Chem. Res. 57, 2024, 2383-2394.